JWE Abstracts 

Vol.14 No.1&2 March 1, 2015

Web Technologies

Editorial (pp001-002)
Angelo Di Iorio, David Rossi, and Stefano Zacchiroli

Surfing the Web Using Browser Interface Facilities: A Performance Evaluation Approach (pp003-021)
Raúl Peña-Ortiz, José Antonio Gil, Julio Sahuquillo, and Ana Pont
The user interaction with the current web contents is a major concern when defining web workloads in order to precisely estimate system performance. However, the intrinsic difficulty to represent this dynamic behavior with a workload model has caused that many research studies are still using non representative workloads of the current web navigations. In contrast, in previous works we demonstrated that the use of an accurate workload model which considers user's dynamism when navigating the web clearly affects system performance metrics. In this paper we analyze, for the first time, the effect of considering the \acl{UBI} as a part of user's dynamic behavior on web workload characterization in performance studies. To this end, we evaluate a typical e-commerce scenario and compare the obtained results for different behaviors that take the user interaction into account, such as the use of the back button and parallel browsing originated by using browser tabs or opening new windows when surfing a website. Experimental results show that these interaction patterns allow users to achieve their navigation objectives sooner, so increasing their productivity up to 200\% when surfing the Web. In addition, results prove that when this type of navigations is taken into account, performance indexes can widely differ and relax the stress borderline of the server. For instance, the server utilization drops as much as 45\% due to parallel browsing behavior.

Exploiting Emoticons in Polarity Classification of Text (pp022-040)
Alexander Hogenboom, Danella Bal, Flavius Frasincar, Malissa Bal,
Franciska de Jong, and Uzay Kaymak
With people increasingly using emoticons in written text on the Web in order to express, stress, or disambiguate their sentiment, it is crucial for automated sentiment analysis tools to correctly account for such graphical cues for sentiment. We analyze how emoticons typically convey sentiment and we subsequently propose and evaluate a novel method for exploiting this with a manually created emoticon sentiment lexicon in a lexicon-based polarity classification method. We evaluate our approach on 2,080 Dutch tweets and forum messages, which all contain emoticons. We validate our findings on 10,069 English reviews of apps, some of which contain emoticons. We find that accounting for the sentiment conveyed by emoticons on a paragraph level -- and, to a lesser extent, on a sentence level -- significantly improves polarity classification performance. Whenever emoticons are used, their associated sentiment tends to dominate the sentiment conveyed by textual cues and forms a good proxy for the polarity of text.

Keyboard Navigation Mechanisms in Widgets: an Investigation on ARIA's Implementations (pp041-062)
Willian M. Watanabe, Rafael Jose Geraldo, and
Renata Pontin de Mattos Fortes
This study presents an investigation on how keyboard accessibility has been delivered in RIA - \textit{Rich Internet Applications}. We conducted an evaluation on 32 websites which contained Tab Widgets and 74 websites which contained Menu Widgets, from the 150 websites of Alexa's top most accessed websites list. The evaluation process consisted of checking if the Widgets implemented ARIA - \textit{Accessible Rich Internet Applications} requirements, like the use of role/state semantic attributes and presentation of keyboard interaction strategies. The results showed that, even though the ARIA specification achieved the status of W3C Candidate Recommendation in 2011 and W3C Recommendation in 2014, few websites implemented Tab and Menu Widgets according to ARIA in the Web. The study also identified alternative keyboard navigation mechanisms that are accessible to Assistive Technologies users, despite the disadvantages they might represent. Moreover, the study proposes a framework to classify these alternative keyboard navigation mechanisms and map the technological requirements which need to be addressed in order to make the Tab and Menu Widgets implement the ARIA specification.

Other Research Articles

Multilevel Analysis for Agent-Based Service Composition (pp063-079)
Arif Bramantoro, Ahlem B. Hassine, Shigeo Matsubara, and Toru Ishida
Agent-based Web service composition has become one of the most challenging research issues. Many composition techniques and formalizations have been proposed, but they are neither mature nor flexible. They assume that each sub-task is an atomic process, hence it cannot be decomposed based on user requirements. Moreover, those techniques and formalizations are not suitable for dynamic environments such as the language service domain. Language service requires a flexible formalization to accommodate the user's language skills in conjunction with QoS. The key contributions of this paper are (\emph{i}) a complete formalization that ideally reflects the nature of real applications and permits extension of the original abstract workflow (in case of failure); (\emph{ii}) a novel agent-based protocol able to find satisfying solutions for this problem in real time to allow restriction and/or relaxation within the original workflow; (\emph{iii}) a hybrid architecture of service-oriented computing and multi-agent systems for implementing Abstract Web service, Information analysis, and User agents. Experiments are presented to find solutions that can be executed within a feasible time and space.

Type-Ahead Exploratory Search through Typo and Word Order Tolerant Autocompletion (pp080-116)
Pavlos Fafalios and Yannis Tzitzikas
There is an increasing interest on recommending to the user instantly (during typing characters) queries and query results. This is evidenced by the emergence of several systems that offer such functionalities, e.g. {\em Google Instant Search} for Web searching or {\em Facebook Search} for social searching. In this paper we consider showing more rich recommendations that show several other kinds of {\em supplementary information} that provide the user with a better {\em overview} of the search space. This supplementary information can be the result of various tasks (e.g. textual clustering or entity mining of the top search results), may have very large size and may cost a lot to be derived. The instant presentation of these recommendations (as the user types a query letter-by-letter) helps the user (a) to quickly discover what is popular among other users, (b) to decide fast which (of the suggested) query completions to use, and (c) to decide what hits of the returned answer to inspect. In this paper we focus on making this feasible (scalable) and flexible. Regarding scalability we elaborate on an approach based on precomputed information and we comparatively evaluate various {\em trie-based} index structures for making real-time interaction feasible, even if the size of the available memory space is limited. Specifically, we show how with modest hardware (like this of a mobile device) one can provide instant access to large amounts of data. Moreover, we propose and experimentally evaluate an incremental procedure for updating the index. For improving the throughput that can be served we analyze and experimentally evaluate various policies for {\em caching subtries}. With regard to flexibility, in order to reduce user's effort and to increase the exploitation of the precomputed information, we elaborate on how the recommendations can tolerate {\em different word orders} and {\em spelling errors}, assuming the proposed trie-based index structures. The experimental results revealed that such functionality significantly increases the number of recommendations especially for queries that contain several words. Finally, we propose an algorithm for computing the top-K suggestions that exploits the ranking information in order to reduce the trie traversals. An experimental evaluation proves that the proposed algorithm highly improves the retrieval time.

An Interactive Web Based Toolkit For Multi Focus Image Fusion (pp117-135)
Veysel Aslantas, Rifat Kurban, Ahmet Nusret Toprak, and Emre Bendes
This paper presents a web-based multi-focus image fusion toolkit developed by using ASP.NET and MATLAB. The toolkit enables users to explore different image fusion techniques such as basic averaging, Laplacian pyramid, wavelet, Discrete Cosine Transform (DCT), pixel based method using spatial frequency & morphological operators (PBSFMO) and block-based spatial domain fusion (SDMIF) methods. The toolkit also includes a new optimal fusion method based on evolutionary algorithms such as Evolution strategies (ES), Genetic algorithm (GA), Differential evolution (DE), and Adaptive differential evolution (JADE) algorithm. Users will be able to evaluate several image fusion techniques easily and efficiently by employing the toolkit.

Prevention of Fault Propagation in Web Service: a Complex Network Approach (pp136-150)
Ying Liu, Shu Mao, Mingwei Zhang, Guoqi Liu, Zhiliang Zhu,
and Jingde Cheng
How to prevent the fault propagation problems in Web Service has become an important issue. The recent research works mostly take some fault tolerance method in service based system. These methods detect or diagnose faults in the composition process, find the failure service, take tolerance action and recover the system. However, in the service oriented architecture, one service is shared by different service based systems. The fault tolerance method only considers from the view of one service user, and tolerance action not considering the whole network would change its load and even the global redistribution of loads over all of the services, trigger a cascade of overload, and result in service network paralysis. The research of cascading failure in Complex Network provides a set of models to help study the above problems. Consequently, this paper proposes a new approach to deal with the fault propagation for Web Service from the view point of the whole service network, which could analyze its resistance influenced by the size of network, different types of attacks and load allocation strategies and prevent the disasters from happening. Firstly, it constructs a Web Service Complex Network (WSCN) composed of single service and their functional similarity. Then it models fault propagation based on WSCN, and simulates the propagation process by analyzing WSCN performance under small attack, large attack, random attack and calculated attack. When fault happens in WSCN, our method uses weight-based and spare-load-based load allocation methods of failed service to compare their influences on the whole network. The experimental results show that when fault happens in WSCN, the network has better resistance for small scale failure than big scale one, and resists stronger for random attack than deliberate one; when the service failure happens, the remaining space based load allocation strategy on it has higher robustness than weight based one. The simulation of fault propagation for Web Service could set example for preventing and reducing probabilities of collapse in the service network.

Analyzing Topological Characteristics of The Korean Blogosphere (pp151-178)
Jiwoon Ha, Duck-Ho Bae, Minsoo Ryu, Sang-Wook Kim, Seok-Chul Baek,
Byeong-Soo Jeong, and Jinsoo Cho
Due to their popularity and widespread use, blogs have become an important medium through which many people communicate and exchange information on the World Wide Web (WWW). The blogosphere has provided many opportunities for individuals and companies to establish new business models that investigate social relationships. In Korea, there are many blogospheres that appear to have characteristics that differ from other foreign blogospheres on the Internet. Consequently, it is inappropriate to apply the analysis methods used for the foreign blogosphere directly to the Korean blogospheres. To establish successful business policies for the Korean blogospheres, it is necessary to understand the characteristics of the Korean blogospheres and the behavioral patterns of the bloggers. In this paper, we analyze the characteristics of the Korean blog network, wherein each blogger forms a node and scraps by bloggers form edges. First, we demonstrate that the Korean blog network is a scale-free network, like the WWW. Second, we compare the bow-tie structure of the Korean blog network with that of the WWW. Lastly, we analyze the changes in the Korean blog network over time. Results of these analyses will be helpful in developing effective algorithms and establishing new business models targeted at the Korean blogosphere.

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