Using co-ordinated atomic actions for building complex Web applications: a learning experience

This paper shows how modern structuring techniques can be employed in integrating complex web applications such as travel agency systems. The main challenges the developers of such systems face are dealing with legacy web services and incorporating means for tolerating errors. Because of the very nature of such systems, exception handling is the main recovery technique to be applied in their development. We employ coordinated atomic actions to allow disciplined handling of such abnormal situations by recursively structuring the integrated system and by associating handlers with such actions. We use protective wrappers in such a way that each operation on legacy components is transformed into an atomic action with a well-defined interface. To accommodate a combined use of several ready-made environments (such as communication packages, services and run-time supports), we employ a multilevel exception handling. We believe that these techniques are generally applicable for both: structuring integrated web applications and providing their fault tolerance.

Exception handling in a complex concurrent and distributed system (e.g. one involving cooperating rather than just competing activities) is often a necessary, but a very difficult, task. No widely accepted models or approaches exist in this area. The object-oriented paradigm, for all its structuring benefits, and real-time requirements each add further difficulties to the design and implementation of exception handling in such systems. In this paper, we develop a general structuring framework based on the coordinated atomic (CA) action concept for handling exceptions in an object-oriented distributed system, in which exceptions in both the value and the time domain are taken into account. In particular, we attempt to attack several difficult problems related to real-time system design and error recovery, including action-level timing constraints, time-triggered CA actions, and time-dependent exception handling. The proposed framework is then demonstrated and assessed using an industrial real-time application-the Production Cell III case study.

While typical solutions focus on fault tolerance (and specifically, exception handling) during the design and implementation phases of the software life-cycle (e.g., Java and Windows NT exception handling), more recently the need for explicit exception handling solutions during the entire life cycle has been advocated by some researchers. Several solutions have been proposed for fault tolerance via exception handling at the software architecture and component levels. This paper describes how the two concepts of fault tolerance and software architectures have been integrated so far. It is structured in two parts (overview on fault tolerance and exception handling, and integrating fault tolerance into software architecture) and is based on a survey study on architecting fault tolerant systems where more than fifteen approaches have been analyzed and classified. This paper concludes by identifying those issues that remain still open and require deeper investigation.

Practical exception handling and resolution in concurrent programs

A relevant consequence of the expansion of the web and e-commerce is the growth of the demand of new web sites and web applications. As a result, web sites and applications are usually developed without a formalized process, and web pages are directly coded in an incremental way, where new pages are obtained by duplicating existing ones. Duplicated web pages, having the same structure and just differing for the data they include, can be considered as clones. The identification of clones may reduce the effort devoted to test, maintain and evolve web sites and applications. Moreover, clone detection among different web sites aims to detect cases of possible plagiarism. In this paper we propose an approach. based on similarity metrics, to detect duplicated pages in web sites and applications, implemented with HTML language and ASP technology. The proposed approach has been assessed by analyzing several web sites and Web applications. The obtained results are reported in the paper with respect to some case studies.

(ProQuest: ... denotes formulae omitted.)1 Research Premises and HypothesisMaintenance costs have a consistent weight in the total costs generated by an application during its entire lifecycle. Previously conducted research and studies that focus on software maintenance support this claim. In [2], the 60/60 rule of software is depicted. The rule claims that maintenance accounts for 60% of the total costs generated by a software in its entire lifecycle. Enhancement or perfective [3] maintenance tasks account for 60% of all the costs generated by maintenance [2], whereas error correction or corrective [3] maintenance tasks account only for 17% of total maintenance costs [2]. In [4] it's stated that software applications evolve over time to meet the changing needs which leads to maintenance generating 67% of the applications total lifecycle costs. In [5] it is argued that maintenance typically accounts for 75% or more of the total software workload. Other relevant research place maintenance costs at 90% [6], 75% [7], 90% [8] or at 60% to 70% [9] of the overall application's lifecycle cost. It is therefore of paramount importance to accurately estimate maintenance cost before implementing a software project in order to better comprehend the total costs associated with developing and owing a software application. Better understanding maintenance costs will provide valuable information regarding resource planning and the appropriate time to decommission the application.The cost of maintenance is directly determined by the number of people involved in the maintenance process and the number of hours each person invests in the maintenance tasks. Thus in order to estimate maintenance cost one needs to estimate the effort invested in the maintenance process. The maintenance effort is expressed in man-hours which entails the number of ours dedicated by the maintenance team to implementing maintenance tasks. Maintenance in web applications has two main components: content maintenance and technical maintenance.Content maintenance requires performing tasks of a non-technical nature like updating product inventory and information, adding news or articles, managing blog posts, updating contact or brand and visual identity information and moderating user comments or messages. Content maintenance team staffing and therefore content maintenance effort is determined by the web application's size [1].According to [1] and as presented in Table 1, content maintenance cost is determined by the number of hours required to keep the web application up to date in terms of content. The larger the application the more hours need to be invested in keeping it up to date in terms of content. The more content changes in an application the more technical maintenance tasks are generated. Technical maintenance tasks are generated because content managers spot bugs or request new functionality to help keep the content up to date. Therefore, content update frequency is a factor that impacts maintenance effort and cost.Technical maintenance requires adding new functionality, performing regular back-ups, monitoring website outages, checking IP reputation, checking DNS configuration, test website speed, check for broken links, perform software updates if third party software was used when developing the web application, monitor traffic statistics and review search engine indexing.According to [1] and as presented in Table 2, technical team stuffing is determined by the level of complexity built into the web application. Thus, a Basic web application which is characterized by static content build mainly using front-end technologies like HTML, CSS and JavaScript will require no more than 1 person to perform maintenance tasks. A Dynamic web application which stores its content in a database and has functionality which is powered by PHP, Java, ASP.NET, Python, Ruby or any other high-level programming language will require 1 to 2 persons to perform maintenance tasks. …

<p>The development of Virtual Reality (VR) and Augmented Reality (AR) technologies has significantly transformed the tourism industry, including travel agencies in Indonesia. This study aims to analyze the adoption level and impact of VR and AR technology implementation in travel agencies in Indonesia. Using the Unified Theory of Acceptance and Use of Technology (UTAUT) theoretical framework<em>,</em> this research combines a literature review, case studies, and interviews as the research methodology. The case studies involve ten of the largest travel agencies in Indonesia that have implemented VR and AR technologies in their marketing strategies. Semi-structured interviews were conducted with representatives from these travel agencies to gain an in-depth understanding of the experiences, challenges, and benefits of implementing VR and AR technologies. The researcher carried out data triangulation by comparing findings from the literature review, case studies, and interviews to ensure the validity of the research findings. The results indicate that the adoption of VR and AR technologies by travel agencies in Indonesia is still in its early stages. However, travel agencies implementing VR and AR technologies report significant positive impacts, such as increased tourist interest, enhanced product differentiation, and improved customer engagement. The case studies demonstrate that implementing VR and AR technologies helps travel agencies promote tourist destinations more innovatively and attractively. Nevertheless, several challenges are also encountered, such as the high cost of developing VR and AR content, regular content updates, and the limited human resources skills needed to operate these technologies. This research contributes to understanding the adoption and impact of VR and AR technology implementation in travel agencies in Indonesia. The findings of this study can assist travel agencies in evaluating the potential adoption of VR and AR technologies and developing effective implementation strategies.</p><p><strong>Keywords:</strong> <em>Virtual Reality, Augmented Reality, travel agencies, adoption level, implementation impact.</em></p>

Coordinated atomic (CA) action is a widely used approach to structuring concurrent activities in distributed embedded applications. Recovery from failures is one of its major concerns. Despite the intuitive simplicity, reasoning about failure recovery in CA actions is rather complex because of the interaction between various system components. This paper proposes an approach based on timed CSP for modelling CA actions and reasoning about different forms of interaction between system components, addressing issues such as failure modes, means of fault-tolerance and fail-safe mechanisms

Developments in today’s information technologies are dazzling. Using information technologies results in having advantages in competition, decreasing costs, gaining time, and getting and sharing information. Now it is possible to state that there are different types of usage within the information technologies. Internet, intranet, e‐mail connections, electronic trade, central reservation systems, and Web applications are some examples. In a rapidly increasing trend, touristic establishments are benefiting from the new information technologies. Evidence of this trend is clearly seen in the advantages to touristic establishments and their budget shares for technology. For example, travel agencies are using the Internet as a communication tool, and hotels are using it to market their goods and services, to receive reservations, and to evaluate customer complaints/suggestions. In this paper, Web sites and Web applications of five‐star hotels operating in the Antalya region were examined.

SummaryThis work presents an extended and enhanced gray‐box combinatorial security testing methodology for SQL injection vulnerabilities in web applications. We propose multiple new attack grammars modelling SQLi attacks against MySQL‐compatible databases, each one targeting a different injection context. Additionally, these grammars are also dynamically refined at the beginning of each attack against an endpoint of a web application, as a further optimization of the used attack model by taking into account the specifics of the generated query of that endpoint. Our goal is to enhance existing combinatorial approaches for detecting SQL injection vulnerabilities. The newly developed methodology is implemented in a prototype security testing tool called SQLInjector+, which is an extension of an earlier prototype developed by us in prior work. This improved tool can attack (i.e. test) any web application that uses a MySQL‐compatible database management system. We evaluate our revised approach and improved prototype tool in a case study comprising of different kinds of web applications to which SQLi is a potential security threat. The case study contains the well‐known verification framework WAVSEP among other five real‐world web applications and one web application firewall. Our generated attack vectors, constructed via combinatorial methods applied to our improved and dynamically optimized attack grammars, are capable of injecting every known vulnerable endpoint in WAVSEP and also of finding new vulnerable parameters in some of the real‐world applications investigated in this paper. Our approach performs equally well or better when compared with existing state‐of‐art of SQL injection security testing tools (sqlmap, w3af, wapiti and fuzzdb) across all tested web applications in the case study.

The integration of complex systems out of existing systems is an active area of research and development. There are many practical situations in which the interfaces of the component systems, for example belonging to separate organisations, are changed dynamically and without notification. Usually systems of system (SoS) developers deal with such situations off-line causing considerable downtime and undermining the quality of the service that SoSs are delivering [Romanovsky & Smith 2002]. In this paper we propose an approach to on-line handling such upgrades in a structured and disciplined fashion. All interface changes are viewed as abnormal events and general fault tolerance mechanisms (exception handling, in particular) are applied to dealing with them. The paper outlines general ways of detecting such interface upgrades and recovering after them. An Internet Travel Agency is used as a case study throughout the paper. An implementation demonstrating how the general approach proposed can be applied for dealing with some of the possible interface upgrades within this case study is discussed.KeywordsResource Description FrameworkTravel AgencySimple Object Access ProtocolException HandlingInterface ChangeThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

A comparative study of exception handling mechanisms for building dependable object-oriented software

Knee abnormalities, such as meniscus tears and ligament injuries, are common in clinical practice and pose significant diagnostic challenges. While traditional imaging techniques—X-ray, Computed Tomography (CT) scan, and Magnetic Resonance Imaging (MRI)—are vital for assessment. However, X-rays and CT scans often fail to adequately visualize soft tissue injuries, and MRIs can be costly and time-consuming. To overcome these limitations, we developed an innovative AI-driven approach that allows for the detection of soft tissue abnormalities directly from X-ray images—a capability traditionally reserved for MRI or arthroscopy. We conducted a retrospective study with 4,215 patients from two medical centers, utilizing knee X-ray images annotated by orthopedic surgeons. The YOLOv11 model automated knee localization, while five convolutional neural networks—ResNet152, DenseNet121, MobileNetV3, ShuffleNetV2, and VGG19—were adapted for multi-label classification of eight conditions: meniscus tears (MENI), anterior cruciate ligament tears (ACL), posterior cruciate ligament injuries (PCL), medial collateral ligament injuries (MCL), lateral collateral ligament injuries (LCL), joint effusion (EFFU), bone marrow edema or contusion (CONT), and soft tissue injuries (STI). Data preprocessing involved normalization and Region of Interest (ROI) extraction, with training enhanced by spatial augmentations. Performance was assessed using mean average precision (mAP), F1-scores, and area under the curve (AUC). We also developed a Windows-based PyQt application and a Flask Web application for clinical integration, incorporating explainable AI techniques (GradCAM, ScoreCAM) for interpretability. The YOLOv11 model achieved precise knee localization with a mAP@0.5 of 0.995. In classification, ResNet152 outperformed others, recording a mAP of 90.1% in internal testing and AUCs up to 0.863 (EFFU) in external testing. End-to-end performance on the external set yielded a mAP of 86.1% and F1-scores of 84.0% with ResNet152. The Windows and web applications successfully processed imaging data, aligning with MRI and arthroscopic findings in cases like ACL and meniscus tears. Explainable AI visualizations clarified model decisions, highlighting key regions for complex injuries, such as concurrent ligament and soft tissue damage, enhancing clinical trust. This AI-driven model markedly improved the precision and efficiency of knee abnormality detection through X-ray analysis. By accurately identifying multiple coexisting conditions in a single pass, it offered a scalable tool to enhance diagnostic workflows and patient outcomes, especially in resource-constrained areas.Supplementary InformationThe online version contains supplementary material available at 10.1038/s41598-025-21895-6.

The integration between technological devices and educational programs can improve students’ learning experience. This is also true when referring to psychological interventions with children to foster emotional competence in relation to disasters. Therefore, within an interdisciplinary project (PrEmT project, Emotional Prevention and Earthquakes in primary school, in Italian Prevenzione Emotiva e Terremoti nella scuola primaria) we developed the web application HEMOT® (Helmet for EMOTions). HEMOT® includes ten levels aimed at promoting knowledge about earthquakes, safety behaviors, emotions, and emotion regulation strategies. We involved 67 second and fourth-graders in a ten-unit training: During each unit they used a level of the web application and participated to traditional activities. The aim of this study was to explore individual differences in perceived usability and performance using HEMOT®, running Latent Class Growth Analyses. We found two different latent groupings for both usability and performance. However, most of the children gradually perceived a decreasing difficulty using HEMOT® and obtained a good performance across the levels. To sum up, this study described two relevant aspects of a web application developed ad hoc to promote earthquake-related emotional prevention with children. On the whole, HEMOT® respects accessibility and usability criteria and its contents are not too demanding for children: It could be considered a useful and fun method to promote earthquake-related emotional prevention.

Purpose This study aims to identify the motivations for the formation of Coopetition in the tourism supply chain among travel and tourism agencies and hotels in the City of Tehran. Design/methodology/approach The present study is qualitative and exploratory. In this study, using the Convenience Sampling method, 21 tourism supply chain activists, including managers and senior experts from hotels and travel and tourism agencies in Tehran, were selected. Then, using semi-structured interviews and coding of the findings through the Clark and Brown method, main themes, sub-themes and conceptual categories were extracted. Findings Finally, regarding the motivations for coopetition among hotels and travel agencies, extracted main and sub-themes resulted in determining four conceptual categories including: Contextual aspect, Managerial aspect, Behavioral aspect and Strategic aspect. Originality/value No research has been conducted so far on the motivations for the formation of coopetition among hotels and travel agencies, specially in the Iranian tourism industry, which is targeted in the present study.