國立交通大學
資訊管理研究所
博 士 論 文
以使用者共識為中心的服務導向塑模方法-
以智慧環境為例
A User Centric Service-Oriented Modeling Approach: A
Case Study on Intelligent Environment
研 究 生 : 程鼎元
指導教授 : 羅濟群 教授
共同指導教授 : 趙國銘 教授
以使用者共識為中心的服務導向塑模方法-
以智慧環境為例
A User Centric Service-Oriented Modeling Approach - A
Case Study on Intelligent Environment
研 究 生 : 程鼎元
Student
:
Ding-Yuan
Cheng
指導教授 : 羅濟群
Advisor : Chi-Chun Lo
共同指導教授 : 趙國銘
Co-Advisor :Kuo-Ming Chao
國 立 交 通 大 學
資 訊 管 理 研 究 所
博 士 論 文
A Dissertation
Submitted to Institute of Information Management College of Management
National Chiao Tung University in partial Fulfillment of Requirements
for the degree of Doctor of Philosophy
in
Information Management November 2010
Hsinchu, Taiwan, Republic of China
中 華 民 國 九 十 九 年 十二 月
以使用者共識為中心的服務導向塑模方法 -
以智慧環境為例
學生: 程鼎元
指導教授: 羅濟群
共同指導教授: 趙國銘
國立交通大學資訊管理研究所博士班
中文摘要
隨著服務導向架構與雲端計算的蓬勃發展，網路服務已成為網際網路趨勢。而服務品質對 於服務的使用者來說則一直是很重要的課題。如何選擇服務對於非功能性的服務品質則可以被視 為一個多目標決策的問題。本研究則是提出一個以使用者為中心的服務導向方法，利用模糊理論 與理想解模式進行使用者共識的計算，將其與服務元件架構結合，用以處理網路服務的選擇，使 其可以同時滿足多個使用者的需求與偏號，並且將其應用在動態的環境。服務的使用者可以利用 語言變數輸入對於服務的評價與偏好，本研究透過轉換成模糊集合表示之，並利用共識積分將其 轉換成數值後，再進行共識的計算。而服務元件架構則是用來將這些計算方法、軟體、硬體可以 快速的結合在一起，提供一個良好整合的平台與環境。 本研究以設計一個智慧環境為案例場景，以冷氣服務、除溼服務與燈光服務為評估的對象， 讓使用者對於不同的溫度、溼度與亮度進行案例的評估，以得到群體使用者對於舒適度最大共識 下的設定值；本研究並利用一個 8*8 的 LED 模擬服務執行的場景，用以證明服務的選擇與執 行可以透過服務元件架構良好的結合在一起。在成熟的資訊通訊技術發展上，可以降低資訊系統 建置的複雜度與異質環境整合的難度。我們也將成功利用的將本研究所提出的方法應用到一個智 慧節能的計劃之中，該計劃是利用資訊通訊技術(Information Communication Technology, ICT)將家庭用電狀況搜集後，利用感測器搜集資料後利用 Zigbee 網路傳回資料中心，經過分析後給予
使用者在使用家電設備時的建議，提供使用者對於節約能源的共識形成有一定的助益。 關鍵字：網路服務，綠能資訊通訊科技，服務決策，群體共識、服務組合架構
A User Centric Service-Oriented Modeling Approach
- A Case Study on Intelligent Environment
Student: Ding-Yuan Cheng
Advisor: Chi-Chun Lo
Co-Advisor: Kuo-Ming Chao
Institute of Information Management
National Chiao Tung University
ABSTRACT
With rapid development of service-oriented architecture and cloud computing, web services have been widely employed on the Internet. Quality of service (QoS) is a very important criterion for service consumers to measure and select services. The selection of web services with respect to non-functional QoS criteria can be considered as a multiple criteria decision making (MCDM) problem when multiple consumers need to share a service. This study presents an evaluation method based on the technique for Order Preference by Similarity to an Ideal Solution to help service consumers to select web services in a fuzzy environment. The linguistic variables, parameterized by triangular fuzzy numbers, are used to evaluate the weight of various criteria and the ratings of each alternative web service. Then the fuzzy TOPSIS method is employed to transform the linguistic terms into crisp numbers and obtain the preference order of available alternative web services.
This paper describes a framework which is featured by integrating fuzzy TOPSIS and service component architecture to facilitate web service selection and to effectively satisfy a group of service consumers’ subjective requirements and dynamic preferences on a cast study on intelligent environment. The proposed framework is also able to re-aggregate users’ feedback on the services which are air-condition, dehumidify, and lighting service. User could evaluate these services and find out the group consensus. We also design a simulated environment that includes 8*8 LED matrix on a circuit board that corresponds to an office with different appliances to demonstrate the dynamic service selection and binding. The simulation is used to assess the computational efficiency of the fuzzy TOPSIS method and the flexibility and efficiency of the proposed system. We also apply the proposed method into a project of ICT for energy efficiency. It not only collected electronic current but also analytic the status of power consumptions from data center by ICT. It helps users to form the consensus on energy-saving and service-using.
Keywords: Web Service, Green ICT, Service Selection, Group Consensus, Service Component Architecture
誌 謝
本論文得以順利完成，首先得感謝我的兩位指導教授－羅濟群教授(台灣) 以及趙國銘教授(英國)於研究過程中的悉心指導。在就讀交通大學碩、博士的修 業過程中，感謝羅濟群教授一路上的教導，使我在研究方向的規劃、研究能力的 養成上能有顯著的進步；在專案開發、研究計劃的經驗，為我累積了許多技術上 的基石，並鼓勵我旅英進行研究，給我長足的時間與空間，使得我能夠有愉快且 充實的國外求學經驗。 在攻讀博士的過程中，幸感謝趙國銘教授耐心的教導，除了使得我在研撰 寫究論文時能夠更加的周嚴，在研究方法、研究討論、論文投稿等許多地方，在 未來人生道路上給了我許多的啟蒙，並深深感謝趙國銘教授旅英期間給予我極大 的協助。兩位老師宏觀的視野，以及給予我的信任讓我無比的力量，感謝兩位指 導教授均對我視如己出，更教導了我研究以外許多存在於人生的智慧，讓我銘感 五內，何其有幸能夠遇到亦師亦友、如同家人般的指導教授。也因為兩位指導老 師細心的教導，讓我在研究的路上更加的虛心與努力，奠下我日後獨立研究的能 力。在此謹致上我最深誠、誠摯的感謝，若不是兩位指導教授給予我如此大的包 容與耐心，我無法順利完成博士論文。 同時，由衷的感謝口試委員陳鴻基老師、張禾坤老師、陳澤雄老師與劉敦 仁老師對於論文的細心審閱與費心的指導，對於本篇論文不吝指出問題與建議， 讓本篇論文的內容能夠更加的充實、完備，並提供相關領域的未來研究方向，對 於口試委員們的寶貴意見，能夠使得文章與未來研究的潤稿與修訂上有著莫大的 幫助。 感謝資管所老師們的細心教導，由於受教於游伯龍老師、楊千老師、林妙 聰老師、劉敦仁老師、李永銘老師、陳安斌老師為我的博士學位奠定了完整的視野。更感謝林營清老師與李麗慧老師的敦敦教誨，讓我為人處事上不致於偏悖。 除了師長們在研究上的教導與指正，也要感謝一路上提攜、協助我的宗智、俊龍、 俊傑、嘉輝、耿杰學長，讓我在困頓不前的窘局下，得以繼續前行；也感謝通訊 網路研究室的許多優秀的同窗，平棋、勇璋、志華、昌民、靜蓉、棉媛…一起研 究討論，感謝光禹、芳儀、慕均替我分擔了許多的準備工作；尤其感謝友義、政 揚、義傑在研究期間的相互支援，為我加油打氣。感謝通訊網路實驗室的夥伴們， 帶給實驗室歡樂的研究氣氛。也謝謝本所助理淑惠姐、以及秀文姐在許多事務上 的幫忙。 由衷感謝研究的過程中給予獎勵的國際扶輪社，使得整個研究發表的過程 得以順利的成行，尤其感謝二伯父-程長和的鼓勵與支持。感謝證券櫃檯買賣中 心、以及耐心與我討論資訊中心的長官與同仁們。感謝勇源教育發展基金會，使 得前往英國研究的計劃得以順利的前往。 最後，尤其要感謝我的父母與家人一路上的支持，從小到大一路給我信任 的爸爸，一路愛我、鼓勵我的媽媽，還有永遠讓著我的哥哥，一直陪伴著我的尹 云，他們讓我帶著夢想起飛，等待我安全的著陸，讓我能夠無後顧之憂地攻讀學 位。感謝和我如手足的傳永與政霆，不止讓我跌倒還有爬起來的勇氣，更讓我有 不怕跌倒的骨氣。如今，完成學業、論文付梓，獻上最真誠的感謝給我愛與愛我 的家人，並與他們分享等待已久的此刻，若不是他們，我恐將無法完成。 本論文謹獻給任何幫助我的人們，謝謝你們。 程鼎元 新竹 國立交通大學資訊管理研究所 中華民國九十九年十二月
Content Index
中文摘要 ... III
ABSTRACT ... IV
誌 謝 ... V
CONTENT INDEX ... VII TABLE INDEX ... IX FIGURE INDEX ... X
CHAPRT 1. INTRODUCTION ... 1
1.1. RESEARCH BACKGROUND ... 1
1.2. MOTIVATION AND OBJECTIVE ... 4
1.3. RESEARCH APPROACH ... 6
1.4. THESIS OUTLINE ... 7
CHAPRT 2. LITERATURES REVIEW ... 8
2.1. GREEN ICT ... 9
2.2. GREEN ICT AND SOA ... 13
2.2.1. Heterogeneous ... 14
2.2.2. Communication Protocol... 15
2.2.3. Machine readable ... 17
2.3. WEB SERVICE SELECTION ... 22
2.4. SERVICE COMPOSITION ... 27
2.4.1. Service Component Architecture (SCA) ... 27
2.4.2. Enterprise Service Bus (ESB) ... 29
2.4.3. Service-Oriented Green ICT framework ... 30
CHAPRT 3. A FUZZY TOPSIS METHOD FOR WEB SERVICE SELECTION ... 35
3.1. FUZZY NUMBER AND FUZZY THEORY ... 36
3.2. AFUZZY TOPSISMETHOD FOR WEB SERVICE SELECTION ... 40
3.3. DESIGN PRINCIPLE OF SERVICE ORIENTED MODELING ... 44
CHAPRT 4. PROPOSED USER CENTRIC SERVICE-ORIENTED MODELING ... 50
4.1. GENERAL DESCRIPTION AND BASIC SCENARIO ... 51
4.2. MODULE DESIGN ... 55
4.2.1. Service Execution Engine ... 55
4.2.2. Data Adapter Service ... 55
4.2.3. Collection Service ... 57
4.2.5. Group Preference Database ... 57
4.2.6. Consensus Evaluation Service-Fuzzy TOSIS Method... 58
CHAPRT 5. CASE STUDY ... 59
5.1. SENARIO I-AN APPLICATION OF GROUP USER CONSENSUS FORMATION ... 59
5.2. SENARIO II -AN APPLICATION OF ICT FOR ENERGY EFFICIENCY ... 70
CHAPRT 6. DISCUSSION ... 76
CHAPRT 7. CONCLUSION AND FUTURE WORKS ... 82
ACKNOWLEDGEMENTS ... 84
REFERENCES ... 84
BIOGRAPHY ... 91
Table Index
TABLE 1COMPARISON OF WEB SERVICE DISCOVERY,SELECTION, AND COMPOSITION ... 24
TABLE 2COMPARISON OF SERVICE COMPOSITION ... 28
TABLE 3LINGUISTIC VARIABLES FOR THE IMPORTANCE WEIGHT OF EACH CRITERION ... 38
TABLE 4LINGUISTIC VARIABLES FOR THE RATING OF EACH ALTERNATIVE ... 38
TABLE 5GRADED MEAN INTEGRATION REPRESENTATION FOR THE IMPORTANCE WEIGHT OF EACH CRITERION ... 39
TABLE 6LINGUISTIC VARIABLES FOR THE RATING OF EACH ALTERNATIVE ... 39
TABLE 7IMPLEMENTATION SUGGESTION ... 52
TABLE 8RATINGS BY USERS WITH RESPECT TO CRITERIA ... 64
TABLE 9THE NORMALIZED DECISION MATRIX ... 65
TABLE 10THE DISTANCE MEASURE ... 66
TABLE 11TABLE OF FBRATING ... 73
TABLE 12TABLE OF FBRATING ... 74
Figure Index
FIGURE 1RESEARCH BACKGROUND OF SOA ... 1
FIGURE 2RESEARCH OBJECTIVE OF THIS STUDY ... 4
FIGURE 3RELEVANT AREAS OF LITERATURE ... 8
FIGURE 4EVOLUTION OF INTEGRATION BETWEEN HETEROGENEOUS INFORMATION SYSTEMS ... 16
FIGURE 5THE REVOLUTION FOR THE WEB SERVICE ... 22
FIGURE 6ARCHITECTURE OF ENTERPRISE SERVICE BUS ... 30
FIGURE 7LIFECYCLE OF MDADEVELOPMENT ... 31
FIGURE 8SOAFRAMEWORK TRACK ... 33
FIGURE 9SOA TEMPLATE FRAMEWORK ... 33
FIGURE 10TRIANGLE MEMBERSHIP FUNCTION ... 37
FIGURE 11THREE PHASE OF SERVICE MODELING ARCHITECTURE ... 44
FIGURE 12SERVICE-ORIENTED MODELING APPROACH ARCHITECTURE ... 45
FIGURE 13LIFE-CYCLE OF OUR PROPOSED SERVICE-ORIENTED APPROACH... 46
FIGURE 14USER CENTRIC SERVICE-ORIENTED MODELING ... 47
FIGURE 15PROTOTYPE SYSTEM ARCHITECTURE ... 50
FIGURE 16SEQUENCE DIAGRAM OF SERVICE SUPPORT THE CONSENSUS-ADJUSTING BETWEEN ESB AND USERS ... 53
FIGURE 17ARCHITECTURE OF ENTERPRISE SERVICE BUS ARCHITECTURE ... 55
FIGURE 18SDOAPI META-DIAGRAM ... 56
FIGURE 19DATA ADAPTER SERVICE OPERATION FLOW ... 57
FIGURE 20LED MATRIX AND SIMULATION DEVICE ... 60
FIGURE 21SMART ENVIRONMENT SYSTEM BASED ON SCA DESIGNED-PRINCIPLE ... 61
FIGURE 22 GUI FOR USER’S PREFERENCE COLLECTION ... 61
FIGURE 23 RDF SAMPLE ... 62
FIGURE 24 SDO OBJECT SAMPLE ... 63
FIGURE 25A HIERARCHICAL STRUCTURE FOR THE WEB SERVICE SELECTION PROBLEM ... 63
FIGURE 26ALTERNATIVES PRESENTS ON A LED MATRIX ... 66
FIGURE 27SAMPLE XML OF SYNAPSE CONFIGURATION ... 67
FIGURE 28SAMPLE LIGHTINGSERVICE OF SOAP MESSAGE ... 68
FIGURE 29IMPLEMENTATION OF MICROCONTROLLER HARDWARE ... 69
FIGURE 30GROUP USERS CHANGE ALTERNATIVE FROM A10 TO A9 ... 69
FIGURE 31FUZZY-TOPSISCOOPERATED WITH DEHEMSSYSTEM ... 72
FIGURE 32GUI OF DEHENS SYSTEM FOR USER BROWSING ... 75
FIGURE 33PERFORMANCE ANALYSIS UNDER DIFFERENCE USERS ... 78
FIGURE 34PERFORMANCE ANALYSIS OF DIFFERENT CRITERIA ... 78
Chaprt 1. Introduction
In this chapter, research background and motivation of the dissertation, and organization of the dissertation are introduced.
1.1. Research Background
With rapid advancement of service-oriented architecture (SOA), the use of web services has made rapid growth. The advantages of Web services are highly interoperable and loosely coupled software components which can be published, located, and invoked on the web. The growing number of Web services available within an organization and on the Web raises the new challenge in search problems which involve service discovery [20], service selection [58], and service composition [9][10] [41] [58][59]. Three layers of SOA depict as Figure 1.
Therefore, service discovery allows service providers to publish service profiles and descriptions in UDDI repositories that store information about businesses, services and other related details. Efforts in this area focus on providing rich and machine-readable representation of service properties, capabilities, and behavior as well as reasoning mechanisms to support automated discovery. Service composition is a process to compose selected services in a logical way to meet the user requirements which can take place at the design time or runtime. Most services are designed as loosely coupled components to increase their independences. The relationship among the services is determined and established at the composition process. In other words, a number of services can be composed as a composite service to provide required functions.
In this study, we discuss the scenario of energy consumption and environment setting issues. Group of people face the problems which need to decide the setting of environment such as brightness, temperature. They would encounter a dilemma which is turn on/off the air-condition or how to set the temperature. The decision making of group people sometimes is hard to making while the choices exist trade-off. Especially, tackling global warming, improving resource management, and reducing carbon are the global challenges that need addressing and treating urgently. Many researchers and organizations mentioned that how the Information and Communication Technology (ICT) effects Green policy and action. Here, we use the ICT instead of Information Technology to represent the idea of Green IT.
However, one of the major issues raised by ICT systems concerns the connection of people and technology. Web Service provides modeling, implementation, and integration. Green ICT is becoming most development direction in industry associations, research issues, and government for reducing negative environment effect. In this research, we will proposed a user centric service-oriented modeling
approach in order to conquer the difficulty between users to decide the environment configuration which is multiple criteria decision making problem, and give a case study on intelligent environment.
1.2. Motivation and objective
Smart home or environment often involves numerous hardware devices and software components to sense and control the environment. The integration of these devices and components is an important task. The communications and interactions among sensors, objects, and human participants, however, are inherently complex, as they often involve different protocols and languages. It can be viewed as configuration problem that requires various components to work together in cooperative and coordinated manner in order to produce an optimized environment to meet the system and user requirements. Service-Oriented Architecture (SOA), which offers a way to view sensors, objects, participants as services, can provide an effective approach to improve their communication and coordination, so the human participants can effectively interact with the system and offer their opinions and preferences through a coherent technology. SOA could be a potential approach to maximize users’ satisfaction degree, and minimize the cost of software design, implementation, application installation, and system maintenance.
A web service, a supporting technology for SOA, can be invoked and executed by a number of consumers simultaneously. Most service discovery and recommending systems recommend a list of services according to the functional and/or non-functional requirements given by service consumers. Thus, the service consumer can choose the best one. This kind of cases is based on an assumption that the cardinality between an instance of service and a service consumer is built upon one to one relationship. However, in some cases such as smart environment, an instance of a service needs to serve a number of consumers. In other words, an instance of a service needs to meet various requirements specified by different service consumers. It, however, can be very difficult to design a service when conflicting requirements occur. For example, the staffs in one office use a collection of the same devices or functions provided by the system. Each function is intended as a service such as light service, air condition service, heating service, and ventilation service, etc. Service consumers could have different preferences or requirements on the services such as room temperature. Some users may subjectively feel hot for the current room temperature, but some may feel cool or comfortable. How to set the temperature for air condition/heating service according to these consumers’ preferences can be a challenging issue. A system would encompass the capacities such as group consensus reaching mechanism to improve system adaptability.
1.3. Research approach
In this research, four research steps are adopted to solve the problems of service composition mentioned above. These are described as follows:
(1) Overall literature review: reviewing the existing works about the Web services, Web services composition, Service Component Architecture (SCA), Enterprise Service Bus (ESB), and the tools for realizing these concepts.
(2) Research concept: we present an evaluation method based on the Technique for Order Preference by Similarity to an Ideal Solution (TOPSIS) to help service consumers to select web services with fuzzy user requirements involved. The linguistic variables, parameterized by triangular fuzzy numbers, are used for evaluating the weight of various criteria and the ratings of each alternative web service. Then the fuzzy TOPSIS method is employed to transform the linguistic terms into crisp numbers and obtain the preference order of available alternative web services.
(3) Architecture development: the proposed framework including Service Component Architecture offers a coherent systematic process and approach to model heterogeneous hardware and software components as services in order to increase flexibility for system configuration and organization in a dynamic environment.
(4) Architecture verification: the proposed approach will be tested through the experiment in this study which demonstrate a case study of intelligent environment. We designed 8*8 LED matrix on a circuit board to simulate an office with different appliances to demonstrate the dynamic service selection and binding.
1.4. Thesis outline
This paper is organized as follows. Section 2 reviews the background and related works. Section 3 concentrates on a number of definitions of fuzzy sets theory which are utilized and presents the fuzzy TOPSIS method in this study. Section 4 provides an illustrative example to clarify the application of the fuzzy TOPSIS method in the problem of selecting QoS-aware web services in order to find out the group consensus on environment setting. Section 5 gives a case study and describes the simulation which shows the services binding and execution by means of a LED matrix device. Performance evaluation and extended case study and are presented in Chapter 6. Concluding and future work are given in Section 7. Finally, the reference are attached at the end of the thesis.
Chaprt 2. Literatures Review
In this chapter, first review the characteristics and related works of Green ICT and Service-Oriented Architecture. We then review web services. Moreover, we discuss some service composition problems which may happen to SOA. Furthermore, a review on the existing approaches on web service selection and an analysis on their pros and cons will be reported. Then, we illustrate a number of group decision making methods that can assist users in reaching consensus. In the end, we introduce the Service Component Architecture for service modeling and composition as well as Enterprise Service Bus for service management and service transportation. This paper also offers insights on these issues from the multiple perspectives of development in industry and research in academic.
Figure 3 Relevant areas of literature
These surveyed researches will be introduced respectively as follows. This chapter is organized as follows. Section 2.1 introduces the Green ICT. Section 2.2 describes Green ICT and SOA. Section 2.3 discuss the research background on web service selection. Section 2.4 focus on service composition.
2.1. Green ICT
In this section, we review the current state-of-the-art in the field of Green
Information Technology (IT), reports several issues and future research directions. The
materials used to conduct this research include journal and conference papers, research projects and websites etc. This work can help the readers to have better understanding of Green IT, and to show how other related technologies can address the challenges of Green IT. Information Communication Technology (ICT) and
Service-Oriented Architecture (SOA) have gained attention in recently.
Service-oriented approaches are used for developing green applications and energy-saving that can be sourced as resource. What new conceptual frameworks and theoretical perspective are appropriate for studying Green ICT (GICT) and service-oriented technology? It is concluded that a more predictive and feasible design/implementation, which can be applied within a service-oriented GICT application.
“Green of ICT” is interested in developing technologies and methods to increase efficiency in ICT energy usage without compromising its performance and Quality of Services. Green of ICT is also known as green computing. It involves different stages of ICT life cycle from hardware system design, manufacturing process, and component maintenance to disposal of computers and their recycling methods. ICT products could be computers, servers, and associates subsystems-such as monitors, printers, storage, network devices, and communications system. Some research projects focus on software design to make use of computers as energy-efficient as possible by developing efficient algorithms, removing unnecessary processes in software flexible resource allocation and effective power management.
1. Substitution CRT with LCD: the substitution of old CRT (cathode-ray tube) with LCD (liquid crystal display) can gain significant efficiency in energy usage and the introduction of long-lift OLED (organic light emitting diode) will enable further improvements.
2. Virtual IT and Organization: the virtualization technologies can reduce the number of physical devices to be deployed and increase the level of their utilization. Virtualization such as data-centre will enable significant reduction in the number of deployment for both servers and storages while end-user devices can be consolidated.
3. Green Computer Room/Data centre: energy efficiency solutions and approaches for design of a data centre can improve organization’s capabilities such as virtualization, automation and orchestration. The approaches could include reconfiguration of aisles to a hot/cold aisle layout, the introduction of pod style enclosed units, having localized cooling solutions for hotspots, adopting thigh performance workloads and making use of free cooling through outside air.
4. Label of energy-saving mark on IT facility: label of energy-saving are the widespread instrument in many country of the world, such as United States, Canada, Australia, United Kingdom, and New Zealand. In the United States and EU, ENERGY STAR label indicates the energy efficiency of ICT equipment to enable users be aware of their efficiency.
5. Recycle and process on IT facility: parts of IT facility may contain some polluting substances. It is important to have appropriate procedures to deal with them during the processes to protect the environment from contamination. So, it does not only consider the main production phases in life cycle namely R&D, manufacturing, use, and disposal, but it also needs to focus on the recycle of computers.
“Green by ICT” stands for using ICT to reduce environment burden, which are applying ICT into various fields and application is to reduce the energy and resource
consumption, and minimize CO2 emissions by using sensor networks or other technologies to offer a sustainable environment. The applications of “Green by ICT” include: Smart City Planning, Smart Grid, Smart Logistics, Food miles, Smart Building, Renewable energy power, Virtual IT, Smart Working, Optimization on power saving, Smart Transportation, Smart Car, Smart Monitor, and Smart logistics etc. Green by ICT has very diverse and broad applications.
Green ICT is a research and application area involving multidisciplinary technologies and concepts such as including automation control, communication and networking, computing, and distributed and embedded system etc. With the rapid development of Green ICT, numerous applications related with these issues have been envisioned. Later, we will give further discussion of the research directions with these applications.
Energy efficiency is increasingly important for information and communication technologies (ICT), because of the increased usage of ICT, together with increasing energy costs and the need to reduce green house gas emissions that decrease the overall energy consumption. Green ICT could affect our lives on various degrees and aspects depending on to the scope of applications such as green city, green building, green office, and green home which could change the way we work and live. EU has great interests on the concept of Green ICT by initiating several research programs to explore new research agendas. We give more descriptions and discussions on smart city, smart building, smart office, and smart home respectively in the following sections.
Most modern cities face the issues related to traffic jam and huge car flow. Traffic management system uses ICT such as sensor, camera, and traffic light control to smooth car flow or reduce traffic volume by adopting Intelligent Transportation System (ITS) technologies which could change the public’s behaviors of using
transports. The public would prefer taking public transport to private car. For examples, the introduction of a real-time road pricing system can make the private car drivers aware of the true cost of usage which is usually much higher than the public ones. ITS road systems can operate the traffic more efficient by funneling traffic via dynamic speed limits and traffic signals to route around congestion. Furthermore, people can search location-based services such as restaurants and shops, real-time traffic reports, smart electrical grids on smart phone through 3G network from Internet in order to reduce unnecessary journeys.
The needs for transportation are growing, as globalization logistics becomes a phenomenon. The logistics activities comprise package, transportation, storage (inventory management), buying, and recycle. As the concerns for the environmental issues rise, firms need to take more into account of the cost associated with reduction of energy consumption and environment pollution in order to reduce its impact on climate change. The green logistics has also received strong research interests from the communities such as Green supply chain, Green purchasing and food miles. By using ICT in logistics, firms can minimize the package materials, the volumes of stock, energy consumption, and mileage to achieve more sustainable balance economic and environment.
From previous discussion, there have been numerous studies in the literature dealing with the diverse of applications. There is considerable disagreement among systems about the design and implementation of the Green by ICT applications. Some practical project have been reported that are based on the concept of wireless sensor network (WSN) and web services. In the following section, we will describe the problems in Green ICT system ,and rethinking how to solve these problems.
2.2. Green ICT and SOA
Green ICT is formed by numerous components such as operation systems, database systems, sensors, control systems and communication protocols facing a set of challenges in integrating and coordinating these heterogeneous systems, enabling technological agility and reducing the complexities of their development platform. The activities involved to address integration challenge include alleviate the barriers caused by heterogeneity in transmission protocols, hardware platforms, and execution processes. Moreover, inconsistent data, incoherent control signals between devices and software system, and tightly-couple programs have increased the difficulties in integration. Also, inconsistent information and data formats between sensors make development tasks harder for developers to design green systems.
To manage those above challenges, system designers and programmers need to adapt service-oriented architecture approach to the design of system structures, models, processes, and operations. Service-Oriented Architecture is a process-centric and component architecture rather than a program-centric IT architecture. Service-Oriented Architecture offers a practical and viable approach to model and assemble services in response to users’ needs. The combination of Service-orientation and Green ICT, a new trend of ICT architecture, becomes a new paradigm for producing loosely coupled and flexible Green application systems. In this new paradigm, all the components, regardless hardware devices or software modules, are considered as services, so the traditional tightly coupled software and hardware components can turn into loosely coupled services.
2.2.1. Heterogeneous
There are several impediments to widespread, heterogeneous data and knowledge fusion. While integrating heterogeneous information system, it could be difficult to deal with three type of problems which are technical, data model, and semantic heterogeneity. We give the detail of challenges in following.
1. Technology Heterogeneity
It means that the data in the process of exchange and transmission needs to consider the difference in stored location, file format, and data type, programming language, or platform.
2. Data Model Heterogeneity
Data model heterogeneity, also known as schema heterogeneity, is another barrier for enabling system interoperability. This occurs due to using incoherent data representation, column naming, and data types in the multiple databases. Many researchers tried to convert different local schema into a global schema which contains a common consistent data model. The existing approaches lack systematic intelligent automatic schema mapping mechanism to ensure that the schema conversion can be carried out efficiently and effectively. The task is a time and resource consuming process, as schema designers may need negotiation to produce a compromised solution.
3. Semantic Heterogeneity
Semantic heterogeneity could result from conflicting data naming, incoherent interpretations on data meaning and data content.
2.2.2. Communication Protocol
The mainframe systems such as the IBM System/360 series which were used mainly for bulk data processing first introduced in the 1960s. One of the main critical mainframe applications was to provide sufficient computational functions for businesses such as enterprise resource planning, and financial transaction processing. The computation result is stored in tapes which are mass storage devices. The availability of communication and networking infrastructures and the mature technology for real-time interactions between systems, real-time trading transactions across companies in the finance markets can be realized. In the beginning period, real-time access was accomplished through socket. Over time, Network File System (NFS) and File Transfer Protocol (FTP) protocols emerged that abstracted out the complexity of sockets. After that, “middleware” software was designed to deal with messaging and communications between servers or peers. Eventually, the ability of applications to compute in distributed environment became feasible through remote procedure calls (RPCs).
The technology coupled with the growing maturity of network enabled many kinds of functions to be called by remote computers. By the 1980s, personal computers had not only widely used but also its computing power exponentially increased. While the price of hardware came down, the number of servers increased significantly. These trends led to two important progresses in distributed computing. In January 2000, the Simple Object Access Protocol (SOAP) based on eXtensible Markup Language (XML) was introduced. It supported system communication to facilitate a much higher degree of interoperability between programming languages.
After that, Web service which was defined by the W3C provided a standard means of interoperating between different application systems over the SOAP protocol with
an XML serialization. Service, an abstraction which encapsulates software to provide functions, is the basic concept in SOA model. Developers can aggregate these services to develop solution for business needs. The evolution of integration between heterogeneous information systems is depicted in Figure 4.
CORBA DCOM Web Service 1960s 1980s 1970s 1970s 1990s 2000 NFS/ FTP Socket Program RPC Tape
2.2.3. Machine readable
Green application systems need to take advantage of environmental information to enhance the interaction with the user. For example, environment monitor applications should be able to deal with fusion of multi-sensor data. Sensor data cover multiple aspects of the environment, such as the location, identity, temperature, humidity, pressure, brightness, activity and state of people, groups and objects, and so on. Many of the captured data are analogous in nature making the chance of finding a specific term quite good. However, the integration of heterogeneous sensor data into a single system can be difficult.
One of key characteristics that green applications should possess is the ability to acquire information from heterogeneous sources, perform context interpretation and carry out dissemination of context to interested parties. Each device or subsystem in the application might contain a set of variables to accommodate raw data about its surrounding environment sent by sensors or other devices. It, however, lacks a well-developed mechanism for defining sensors, their attributes and classifications. It also does not have a standard high level language to prescribe the required inputs and outputs as well as to control their actions.
Green applications acquire information from surrounding environments through sensors or from other information systems where the events take place. It needs to establish an information and knowledge level of collaborative grid among green computer systems to share and reuse machine-interpretable conceptualizations to maximize their utilities. The realization of semantic web and ontology is one of most promising approaches to meet this need.
There are a number of languages available for representing the concepts in ontology e.g. RDFS (Resource Description Framework Schemas), OWL (Web Ontology Language), and OWL-S. Ontologies provide end-user service and ICT
support system developers a common base for efficient and effective services definitions as well as integration and utilization of ICT systems and resources. Therefore, a solution to integrate the data from multiple sources or interpret the semantic of heterogeneous sensors with different capability is needed in green application systems. To support these tasks in a context-awareness system is needed and more often it is based on ontologies that enable reasoning automatically and efficient knowledge sharing from traditional stand-alone systems to the highly distributed green ICT system.
There are many standards and middleware equipped with different protocols such as Java Intelligent Network Infrastructure (JINI), Home Audio/Video Interoperability (HAVi) and Universal Plug and Play (UPnP), and Open Service Gateway Initiative (OSGi) for connecting heterogeneous systems. JINI, however, cannot directly interact with some devices such as TVs due to lack of HAVi. Although it can use a service gateway to control and connect different appliances, it leads to different levels of difficulties in usage and maintenance. These technologies offer different alternatives for interconnecting heterogeneous devices and services. UPnP supports ad-hoc networking for devices and services, and it is easy to develop. OSGi specification defines a service framework to support multiple Java based devices to run collaboratively, so a new device can be easily added to an executable environment using plug-play technology in order to increase flexibility and dynamics of a system.
1. Remote Method Invocation (RMI)
Remote Method Invocation (RMI) is a Java application programming interface that is equivalent of remote procedure call (RPC). RMI enables a client to obtain a reference of the remote object and to execute it. RMI with IIOP protocol provides the core interfaces and mechanisms for the client and server to communicate through stub and skeleton objects. Even though it has naming service to search the required objects,
semantics for naming service is not supported. Besides, it only supports interoperability between JVMs, non-Java embedded systems have difficulty to participate.
2. CORBA
CORBA, proposed by OMG, provides technical standards for integration and collaboration for heterogeneous application systems. Distributed software based on CORBA objects can increases its reusability and expandability. Many researchers take the advantages of these features to develop middleware environments to support large scale distributed applications. The Interface Description Language (IDL) is a programming language independent specification to describe the interface for client and service communication, so CORBA supports multiple languages and platforms. CORBA was widely accepted technologies by academic and industry communities, but it lost its popularity due to its complexity and industry commitments.
3. JINI
JINI based on the Java technology was developed by Sun Microsystems for spontaneous services and resources networking. JINI provides the ability to assemble service component and cope with distributed computing.
4. HAVi
Home Audio Video Interoperability (HAVi) is a standard specification for connection, communication protocols and APIs that allows Audio and Video hardware products from different vendors to be networked together and controlled from one primary device. HAVi offers plug-and-play capabilities for smart home configuration and it models home networking services as software element. Each object has a unique name and identifier. Objects use messaging to request services from other objects. The advantage of HAVi is that it can bridge with JINI to extend its greater services. The problem is that the actual message passing may differ between vendors.
5. UPnP
Universal Plug and Play (UPnP) is Microsoft peer-to-peer networking initiative. UPnP supports ad-hoc networking for devices and services, and it is easy to develop. Further, it has minimal configuration requirement, and its automatic discovery process uses IP address which is compatible with the existing protocol such as TCP/IP, UDP, HTTP and XML, so a device can leave the network smoothly and automatically. Both controllers and devices can be implemented on a variety of platforms including personal computers and embedded systems.
6. X10
Power-line networking is increasingly becoming an important component for home networking systems. X10 is a standard for communication among electronic devices which are used for home automation using power-line wiring for signaling and controlling. It belongs to horizontal integration between physical devices.
7. OSGi
The protocols mentioned above are not compatible with each other due to their design, so without introduction of extra mechanism to them the communication among them is impossible. The Open Services Gateway Initiative (OSGi) is a universal middleware supported by industry paving a standard way to connect devices such as home appliances and security systems to the Internet. OSGi framework can integrate popular protocols such as UPnP, Jini, DPWS, Zigbee, and Bluetooth. With the application of extensible technologies based on OSGi framework and the supports of context-awareness mechanism, ‘off-the shelf’ affordable smart house could become available to the market, so the user can install monitoring devices or others without the aid of engineers.
Green ICT system could shift its focus on the adoption of service-oriented architecture for system design and implementation to alleviate the insufficiency in
integration and interpretability. They also need to transform traditional tightly coupled modules into more loosely coupled services. Although they need to sense environmental changes, receive messages from other sub-systems, and produce appropriate responses, they need to have capability to reallocate their resources dynamically according to demands and priorities. In such heterogeneous systems, the resources which could be software or hardware can be considered as services. The software would be composed by a number of other software components to perform certain functions. The hardware can be devices such as smart lighting, smart table, or sensors which are responsible for controlling environments and collecting information about changes.
Service-Oriented Architecture (SOA) offers a practical and viable approach to implement services. The key advantages of Web services provide capability for developers to create applications through reuse of existing loosely coupled components and utilization of Web protocols and open XML standards to enable interoperability between systems. From service consumers’ point of view, it is important for service consumers to answer three questions: what services are required; where they are located; how the service can be invoked. In other words, there are three questions corresponding to three key mechanisms service discovery, service selection, and service composition in SOA. Similarly, service consumers could be an end user or a service. In this section, we discuss four major characteristics and research directions. Four major characteristics are composed of framework, middleware, automatic control, and semantic sensor network.
2.3. Web Service Selection
Service contains a collection of functions. Services can be classified into atomic or composite services [43]. An atomic service is a basic unit which cannot be decomposed further. Atomic services on their own normally cannot satisfy the full requirements given by the users, so they need to be composed. A composite service is made of a collection of existing services which can be atomic or composite. Service selection is an important step in service composition. Service providers could offer a variety of applications and services with similar functions and QoS. They can publish their services on UDDI repositories, so a consumer could search her/his required services according to some keywords or other criteria. However, the consumer may discover a collection of services providing same function, so a service selection process based on non-functional attributes to refine possible services is required. Once the appropriate services have been identified and selected, the composition process can take place. The following diagram shows their relationship (see Figure 5). The rest of this section will give more detailed reviews on these topics.
Centralized Decentralized
Service Discovery Service Selection Service Composition Work Flow
Rule-Based Modeling AI-Planning
Registry Static Binding
Dynamic Binding
Provider Publish User Search Service Execution
Many researches focus on facilitating service-oriented system development by proposing different service discovery protocols [24][50][56] to increase accuracy in service discovery and selection. One of the most widely used protocols for publishing service is Universal Description, Discovery and Integration (UDDI) specification [5] that enables service specification to be advertised in a service registry. In our previous studies on the UDDI specification [37], we used the tModel to represent the QoS for web services discovery, selection, and composition. Several researchers have designed the semantic query mechanism into UDDI registry to map RDFS upper concepts with semantics to UDDI data model to increase the precision in service selection [2] [3][34].
Catalogues and P2P solutions are the well-known techniques in Web Service Discovery. In Catalogues, the services are stored in a central node which provides a standardized specification framework as meta-schema to describe services for service discovery and advertisement such as UDDI. When a number of UDDI nodes exist in a network and can be linked together, so they become a decentralized architecture and can be regarded as a virtual node, this is called UDDI cloud or federation [46]. P2P-based Web service Discovery (PWSD) presented in [49][51] is built upon Peer-to-Peer (P2P) technologies which provides a distributed environment and infrastructure for service routing and service locating. So each node in the network provides routing and data location service and also acts as a server providing service access. PWSD also includes ontologies to publish and search for web services descriptions. An agent-based solution proposed in [44][65] called DASD (DAML Agents for Service Discovery) enhances effectiveness in service discovery and selection with an intelligent mechanism. It provides a matchmaking service that allows web service consumers and providers to discover each other more efficient.
A number of researchers have introduced different approaches such as workflow-based approach, Artificial Intelligent (AI) planning, and other modeling methodologies to the service composition process. Semantic Web Service composition methods are based on Model-Driven Architecture (MDA) [6][47][66], and UML [4]. These composite services are specified by using standard UML model to generate system specifications and using MDA approaches to produce applications. Composing services to form an application is a complex and error-prone task, so researchers in AI have proposed different planning techniques in attempt to automate the composition process.
Most existing service discovery or selection techniques, however, do not take into account service customers’ preferences and opinions. Huang et al [20] applied semi-order preference model and content-based service discovery concept to improve effectiveness in service discovery and selection. Their work attempts to assist service providers and consumers in discovering appropriate services by considering their opinions and preferences. Wang et al [58] introduced a new QoS-aware service selection approach by including a fuzzy model to prioritize the service consumers’ and providers’ QoS preferences as they often cannot be expressed precisely and they are normally associated with uncertainty.
Table 1 Comparison of Web Service Discovery, Selection, and Composition
Acceptable Criteria Service Discovery Keyword, Semantic, Attribute, Functional
Service Selection Keyword, Semantic, Attribute, Functional, QoS requirement Service
Composition
Keyword, Semantic, Attribute, QoS requirement, Functional requirement, Nonfunctional requirement
From the previous discussion, the web service selection and composition is one of the decision making for user to determinate. However, decision making can be one of the most complicated administrative processes in management. In the
decision-making process, decision maker may suffer affected by multiple criteria for evaluation. Moreover, Multiple Criteria Decision Making (MCDM) is one of the most well known branches in decision making. MCDM can be divided into two categories: MODM and MADM. A further discussion about MODM and MADM can refer to Hwang and Yoon [23]. Thus, MADM has been widely used by decision makers in management processes to evaluate and rank possible alternatives.
In the decision making processes, a group of decision makers could be involved and it is called Group Decision Making (GDM), so members’ opinions or preferences have to be considered. Most of the GDM problems are of strategic dimensions and can be complicated due to their multi-criteria framework involving many subjective and quantitative factors. Optimal utilization of the time and resources is a key element sought by many GDM methods. Various researchers have focused their attention on increasing the ability of the group to make the quality decisions [6], [8], [11], [18], [19], [23], [27], [28], [52], and[63].
An effective web service discovery mechanism should be able to search and assess services based on their QoS and service contents as well as users’ requirements. The service assessment or selection often involves multi-criteria decision-making process [31]. So, the GDM is applicable to service selection when the service consumers have inconsistent or conflicting requirements, as it can be considered as a reasoning process for reaching group consensus on their requirements for service selection.
TOPSIS method has become a popular multiple criteria decision technique due to (1) its theoretical rigorousness [17], (2) a sound logic that represents the human rationale in selection [55], and (3) the fact that it has been proved in [64] as one of the best methods in solving rank reversal. Recently, some researchers have focused on developing fuzzy TOPSIS methods to deal with imprecise information. Sun et al [56]
applied fuzzy TOPSIS to evaluate the competitive advantages of shopping websites. Chamodrakas et al [16][65] employed fuzzy TOPSIS to help suppliers evaluate customers within the purchase order acceptance process so that the resource allocation and the priority of orders could be optimally identified. Chu et al [14] designed a fuzzy TOPSIS model based on interval arithmetic of fuzzy numbers. Kahraman et al [30] proposed an interactive group decision making methodology based on fuzzy TOPSIS to select information system providers under multiple criteria. Chen et al [15] extended the TOPSIS method based on interval-valued fuzzy sets in decision analysis. Abo-Sinna et al [1] extended the TOPSIS approach to solve multi-objective large-scale non-linear programming problems with block angular structure. Lin et al [34] applied fuzzy TOPSIS for order selection and pricing for make-to-order products when orders exceed production capacity. Li [36] developed a Compromise Ratio (CR) methodology for fuzzy multi-attribute group decision making (FMAGDM), which is an important part of decision support system. Wang and Chang [60][58] utilized fuzzy TOPSIS to help the Air Force Academy in Taiwan select optimal initial training aircraft under fuzzy environment. Wang and Lee [61] generalized TOPSIS to fuzzy multiple-criteria group decision-making by proposing two operators, Up and Low, which satisfy the partial ordering relation on fuzzy numbers, to find positive and negative ideal solutions.
2.4. Service Composition
Achieving service compositing dynamically, there are two important concepts which are Service Component Architecture and Service Execution Engine. In the end, we introduce the Service-Oriented framework and Green ICT. We describe the detail in the following sections.
2.4.1. Service Component Architecture (SCA)
Service Component Architecture (SCA) [41] is a set of specifications which describe a model for building applications and systems by composing and deploying new and existing service components. SCA builds upon an open standard such as Web services and complements to the existing approaches in service implementation. It is based on the idea that business function is supported by a series of services, which can be assembled together to create solutions and to serve a particular business need. The composite applications can contain both new services and business functions from existing systems and applications [12][68].
Furthermore, SCA is aimed to encompass a wide range of technologies to support service component accessibility and web service connectivity. For components, this includes not only different programming languages, but also framework and environments commonly used with those languages. These binding technologies include Web services, Message systems and CORBA IIOP. Bindings are handled declaratively and independent of the implementation. Thus, we can develop a smart system regardless of programming languages. The SCA assembly model deals with the aggregation of components and the linking of components through wiring. The client and implementation specifications address the required services and client side programming.
The SCA specification is divided into a number of documents, each documents dealing with a different aspect of SCA. SCA assembly model deals with the aggregation of components and their linkages. The assembly model is independent of implementation language. SCA is a set of specifications which is used to build applications and systems by deploying new service and composing existing components. The Assembly Model deals with the aggregation of components and the linking of components through wiring using composites. In SCA, a composite is a collection, or assembly, of components or services. A composite considered a “service” when it’s wrapped for external consumption. Furthermore, a composite can contain properties and reference to other components or services. A component is not necessarily intended to be exposed for external consumption. A service in SCA is a self-contained unit of functionality. The benefits of building software based on the reusable building blocks of components and composites have been espoused for several decades. Moreover, SCA does not only extend and complement prior approaches to implementing services, but also provide a programming model for building applications and systems based on a SOA.
Table 2 Comparison of service Composition
Service Composition Method Service Binding Dynamic Flexible Feasible
Static Web Service Composition
Fixed Low Low Easy
Dynamic Web Service Composition
Run time Binding
2.4.2. Enterprise Service Bus (ESB)
The heritage of ESBs is derived from enterprise application integration (EAI). Enterprise Service Bus (ESB) provides a run time environment for service binding and execution environment. One important advantage is that an ESB allows architects to exploit the value of messaging without writing code. In an enterprise application system making use of an ESB, an application will communicate via the bus, which acts as a message broker between applications. When the ESB receives a message, it routes the message to the appropriate application. ESB provides a good data connectivity that includes HTTP (SOAP), XML, FTP, SFTP, File, JMS, et al. Hence, data transfer between different services under multiple protocols can implement easily. Furthermore, UDDI binding component is used to look up service by using the UDDI protocol. A good data connectivity that provided the interface for sender and receiver. For example, email binding for sending and receiving emails though IMAP, POP3 and SMTP.
Moreover, File Binding (FB) connectivity provides a transport service to a file system. A transport service pools inbound message and stored into a file in a specified directory on server side. On the other hand, for client side put message into file in a designated directory. There exists a defect for inbound message processing which is prohibited overwriting by threads. It only once written by one thread in the same time. Hence, data transfer between different services under multiple protocols can be implemented straightforwardly. In our development environment, we use the diverse binding property of ESB to achieve transparent between services.
ESB supports flexible data transformation and intelligent routing which can provide content-based routing based on message properties or inline statements in XML via XPath and XSLT. Furthermore, the custom API enables developers to add
customized adapters or components in the ESB. Individual applications or services can be attached to the bus via adapters. The architecture of ESB is shown as follows (see Figure 6).
SOAP FTP SFTP JMS
XML J2EE .NET WSDL
Enterprise Service Bus
Data Transformation & Content Routing
SOAP JCA Message
Figure 6 Architecture of Enterprise Service Bus
2.4.3. Service-Oriented Green ICT framework
There are several ways to compose services at the design time. Model-driven Architecture (MDA) is a software architecture framework proposed by the Object Management Group (OMG). MDA consists of a set of standards that assist the system in creation, implementation, evolution and deployment. The key technologies of MDA are Unified Modelling Language (UML), Meta-Object Facility (MOF), XML Meta-Data Interchange (XMI) and Common Warehouse Metamodel (CWM).
MDA emphasized the importance of modeling for the software architecture design. MDA suggests a three-layered approach. The Computation Independent Model (CIM) describes a system from the computation-independent point of view to address structural aspects of the system. The Platform Independent Model (PIM) defines a system in terms of a technology-neutral virtual machine or a computational abstraction. The Platform Specific Model (PSM) consists of a platform model that captures the technical platform concepts and a model geared towards the implementation technique. The lifecycle of MDA development is shown as Figure 7.
Figure 7 Lifecycle of MDA Development
There are four kinds of models in MDA. During initial phase, the business analyst analyzes the user requirement in CIM. Next, the PIM based on the outcomes derived from the previous phase to define the functionalities, the structure, and the behavior of a system. The PSM focuses more on implementation and execution platform which could be a specific programming language or database.
Context-awareness is an essential aspect for service utilization, especially when frequent interactions take place between users and environments. In this paper, a solution for developing context-aware web services applications is proposed. The methodology includes a model driven approach to separate the web application functionality development from the context adaptation at the development phases (analysis, design, and implementation). In essence, context adaptation takes place on top of the web application business functionality to facilitate system evolution.
SOA framework provides an easy and uniform way for service composition in a controlled environment, and leverages Web service standards with efficient communication mechanisms. Various definitions of SOA have been given by different
groups, vendors, and business analysts. W3C defined SOA as: "A set of components which
defined SOA as: "The policies, practices, frameworks that enable application functionality to be provided and consumed as sets of services published at a granularity relevant to the service consumer that can be invoked, published and discovered, which are abstracted away from the implementation using a single, standards based form of interface." Gartner defined SOA as: "Service-oriented architecture is a client/server software design approach in which an application consists of software services and software service consumers (also known as clients or service requesters). SOA differs from the more general client/server model in its definitive emphasis on loose coupling between software components, and in its use of separately standing interfaces." IBM defined SOA as: "A Service-Oriented Architecture is an enterprise-scale IT architecture for linking resources on demand. These resources are represented as business-aligned services which can participate and be composed in a value-net, enterprise, or line of business to fulfill business needs. The primary structuring element for SOA applications is a service as opposed to subsystems, systems, or components."
The service-oriented applications are different from traditional software architecture, as the traditional software is relative static at runtime compared with service-oriented ones. Therefore, a new service-oriented application can be composed at runtime using existing services. In the Green ICT, it not only provides a framework for the software design and deployment, but also offers an analytic way to indentify services. In the SOA approach, a lot of physical and logical entities can be considered as services, for example, infrastructure as a service, platform as a service, software as a service (SaaS), device as a service, data as a service and etc. In order to coordinate these services, a well governance of SOA architecture is needed. IBM proposed a SOA Framework that reviewed from the two type views of service consumer and service provider. The SOA Framework can see Figure 8and Figure 9.
Figure 8 SOA Framework track1
Figure 9 SOA template Framework 2
These services based on the framework can be organized into grids. Grids are the platform to enable collaboration and aggregation of heterogeneous resources such as high-speed supercomputer, cluster, store repositories, database, and application
1 Armonk, NY, December 16, 2003. Available at:
http://www.ibm.com/developerworks/webservices/library/ws-soa-enterprise2/ (Last accessed on 15.09.2010). Also available at: . http://www.allhands.org.uk/submissions/papers/81.pdf
2 Mamdouh Ibrahim, Gil Long, Service-Oriented Architecture and Enterprise Architecture, Part 1: A
framework for understanding how SOA and Enterprise Architecture work together, http://www.ibm.com/developerworks/webservices/library/ws-soa-enterprise1/
systems owned by multiple organizations or individuals which are connected by networks. Grid system architecture based on Web service concepts and technologies, which include large-scale data management, information transfer, and distributed computing, gains its momentum and becomes a popular trend.
Thus, the OpenGridForum defined necessary standards for grid architecture and explored their practicality to gird based applications and infrastructures in distributed computing. The Open Grid Service Architecture (OSGA) represented an evolutionary grid system architecture based on web service concepts and technologies. The Open Grid Service Infrastructure (OGSI) provided a distributed system framework which can offer the standard factory and registration interface for creating and discovering grid services.
Chaprt 3. A FUZZY TOPSIS METHOD FOR WEB SERVICE
SELECTION
The Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) method, which is initially proposed by Hwang et al [21], is one of the best-known multiple criteria decision making (MCDM) methods. The TOPSIS method introduces the shortest distance from the positive ideal solution (PIS) and the farthest distance from the negative ideal solution (NIS) to determine the best alternative. While the PIS is to maximize benefit criteria and minimize cost criteria, the NIS is to maximize cost criteria and minimize benefit criteria.
TOPSIS uses triangular fuzzy numbers representing linguistic variables of the weights of criteria and of the ratings of web services which can be transformed into crisp numbers. The transformation is performed by the graded mean integration representation method proposed by Chou [12]. The canonical representation of the addition and the multiplication operations on triangular fuzzy numbers is then used to obtain the PIS and the NIS. To avoid the problem with doubling weightings on each alternative, the distance of each alternative web service from the PIS and the NIS is measured by Minkowski distance function [39][40]. As a result, the preference order of available alternative web services can be identified accordingly. Based on the graded mean integration representation of triangular fuzzy numbers and the canonical representation of addition and multiplication on triangular fuzzy numbers, the procedure of fuzzy TOPSIS method can be performed in an efficient way. This property can reduce the computational complexity in the decision making process.
3.1. Fuzzy Number and Fuzzy Theory
In this section, some basic and related definitions of fuzzy sets will be briefly reviewed.
Definition 1. Fuzzy set. Let X be a universe of discourse. Where à is a fuzzy subset of
X; and for all x∈X, there is a number μÃ(x)∈[0, 1] which is assigned to represent the membership of x in Ã, and is called the membership of Ã.
Definition 2. Normality. A fuzzy subset à is normal if and only if
( )
, A 1.
x
x μ x
∃ ∈ ∨ % = (1)
Definition 3. Convexity. A fuzzy subset à is convex if and only if
(
)
(
1 1 2)
( )
1( )
2 , 1, 2[ ]
A x x A x A x x x X
μ λ% + −λ ≥μ% ∧μ% ∀ ∈ ,∀ ∈λ 0,1 . (2)
Definition 4. Fuzzy number. A fuzzy number à is a normal and convex fuzzy subset
of X.
Definition 5. Triangular fuzzy number. Let à as a fuzzy set and its values will be
located between 0 and 1. It is a triangular fuzzy number à can be defined by a triplet(a, b, c), as shown in Fig. 1. Its membership function is defined as
0, if , , if , , if , 0, if . A x a x a a x b b a c x b x c c b x c μ < ⎧ ⎪ − ⎪ ≤ ≤ ⎪ − = ⎨ − ⎪ ≤ ≤ ⎪ − ⎪ > ⎩ % (3)
