XP中若干实践的探讨

XP是适合中小型团队在模糊或迅速变化的需求的情况下使用的轻量软件开发过程。文章首先分析了XP中的几个关键实践：简单设计、测试、结对编程和重构，并针对某些应用背景下可能存在的问题提出了相应的修改建议。然后，以举例的方式具体说明如何运用XP的实践。最后，通过XP与传统软件开发方法的比较．分析了XP的主要特征和适用性。     

大型复杂项目的极限编程改造方案

由于在大型复杂项目中,存在多支使用不同软件过程的开发团队,多组具有不同要求的、分布在不同地理位置的客户,因此在大型复杂项目中采用极限编程(XP)开发时,标准的XP实践必须加以改造。该文提出一种适应大型复杂项目的XP改造方案。实践证明,通过XP扩展和改造,能够保证代码质量,帮助项目在进度内交付。     

Analysis tools in the study of distributed decision-making: a meta-study of command and control research

Our understanding of distributed decision making in professional teams and their performance comes in part from studies in which researchers gather and process information about the communications and actions of teams. In many cases, the data sets available for analysis are large, unwieldy and require methods for exploratory and dynamic management of data. In this paper, we report the results of interviewing eight researchers on their work process when conducting such analyses and their use of support tools in this process. Our aim with the study was to gain an understanding of their workflow when studying distributed decision making in teams, and specifically how automated pattern extraction tools could be of use in their work. Based on an analysis of the interviews, we elicited three issues of concern related to the use of support tools in analysis: focusing on a subset of data to study, drawing conclusions from data and understanding tool limitations. Together, these three issues point to two observations regarding tool use that are of specific relevance to the design of intelligent support tools based on pattern extraction: open-endedness and transparency.     

Cryptographic and Physical Zero-Knowledge Proof Systems for Solutions of Sudoku Puzzles

We consider cryptographic and physical zero-knowledge proof schemes for Sudoku, a popular combinatorial puzzle. We discuss methods that allow one party, the prover, to convince another party, the verifier, that the prover has solved a Sudoku puzzle, without revealing the solution to the verifier. The question of interest is how a prover can show: (i) that there is a solution to the given puzzle, and (ii) that he knows the solution, while not giving away any information about the solution to the verifier. In this paper we consider several protocols that achieve these goals. Broadly speaking, the protocols are either cryptographic or physical. By a cryptographic protocol we mean one in the usual model found in the foundations of cryptography literature. In this model, two machines exchange messages, and the security of the protocol relies on computational hardness. By a physical protocol we mean one that is implementable by humans using common objects, and preferably without the aid of computers. In particular, our physical protocols utilize items such as scratch-off cards, similar to those used in lotteries, or even just simple playing cards. The cryptographic protocols are direct and efficient, and do not involve a reduction to other problems. The physical protocols are meant to be understood by “lay-people” and implementable without the use of computers. Research of R. Gradwohl was supported by US-Israel Binational Science Foundation Grant 2002246. Research of M. Naor was supported in part by a grant from the Israel Science Foundation. Research of B. Pinkas was supported in part by the Israel Science Foundation (grant number 860/06). Research of G.N. Rothblum was supported by NSF grant CNS-0430450 and NSF grant CFF-0635297.     

Acceptance of software process innovations – the case of extreme programming

Extreme programming (XP), arguably the most popular agile development methodology, is increasingly finding favor among software developers. Its adoption and acceptance require significant changes in work habits inculcated by traditional approaches that emphasize planning, prediction, and control. Given the growing interest in XP, it is surprising that there is a paucity of research articles that examine the factors that facilitate or hinder its adoption and eventual acceptance. This study aims to fill this void. Using a case study approach, we provide insights into individual, team, technological, task, and environmental factors that expedite or impede the organization-wide acceptance of XP. In particular, we study widely differing patterns of adherence to XP practices within an organization, and tease out the various issues and challenges posed by the adoption of XP. Based on our findings, we evolve factors and discuss their implications on the acceptance of XP practices.     

基于智能卡的电子商务认证

智能卡小巧易于携带，有较强的计算能力及存储用户简要表、加密和非加密数据的大容量空间，并且支持电子商务应用。本文首先讨论了传统电子商务认证面临的问题，然后给出了基于智能卡的安全认证机制。     

Lifelong Adaptation in Heterogeneous Multi-Robot Teams: Response to Continual Variation in Individual Robot Performance

Generating teams of robots that are able to perform their tasks over long periods of time requires the robots to be responsive to continual changes in robot team member capabilities and to changes in the state of the environment and mission. In this article, we describe the L-ALLIANCE architecture, which enables teams of heterogeneous robots to dynamically adapt their actions over time. This architecture, which is an extension of our earlier work on ALLIANCE, is a distributed, behavior-based architecture aimed for use in applications consisting of a collection of independent tasks. The key issue addressed in L-ALLIANCE is the determination of which tasks robots should select to perform during their mission, even when multiple robots with heterogeneous, continually changing capabilities are present on the team. In this approach, robots monitor the performance of their teammates performing common tasks, and evaluate their performance based upon the time of task completion. Robots then use this information throughout the lifetime of their mission to automatically update their control parameters. After describing the L-ALLIANCE architecture, we discuss the results of implementing this approach on a physical team of heterogeneous robots performing proof-of-concept box pushing experiments. The results illustrate the ability of L-ALLIANCE to enable lifelong adaptation of heterogeneous robot teams to continuing changes in the robot team member capabilities and in the environment.     

The Impact of an Agile Methodology on the Well Being of Development Teams

This paper describes an empirical study, which addresses the aspect of well being amongst members of the software development teams. The question of interest is whether an agile methodology has any distinct effect on the well being of the software developers. Both quantitative and qualitative methods were utilised, including the participative observation, focus group interviews, close-ended questionnaires and simple statistical tests such as Spearman Correlation and Mann–Whitney test. Initial results showed that an agile methodology (XP) has a positive effect on the level of enthusiasm of the software developers in the most dynamic project. To understand why XP can increase enthusiasm, results are interpreted with references to cognitive, affective and managerial properties of the practices studied. This result needs further investigation on the individual effects of each practice on the wellbeing and attitudes of Software Engineering (SE) teams.     

Physical hypermedia: Augmenting physical material with hypermedia structures

This paper introduces the notion of physical hypermedia, addressing the problem of organizing material in mixed digital and physical environments. Based on empirical studies, we propose concepts for collectional actions and meta-data actions, and present prototypes combining principles from augmented reality and hypermedia to support organization of mixtures of digital and physical materials. Our prototype of a physical hypermedia system is running on an augmented architect's desk and digital walls utilizing Radio Frequency Identifier (RFID) tags as well as visual tags tracked by cameras. It allows users to tag physical materials, and have these tracked by readers (antennas) that may become pervasive in our work environments. In the physical hypermedia system, we work with three categories of RFID tags: simple object tags, collectional tags, and tooltags invoking operations such as grouping and linking of physical material. In addition, we utilize visual ARToolKit tags for linking and navigating 3D models on a physical desk. Our primary application domain is architecture and design, and so we discuss the use of augmented collectional artifacts primarily for this domain.     

A comprehensive study of document security system,open issues and challenges

The privacy and security of identity documents like Passports, PAN cards, Driving License as well as other important personal documents like academic degree certificates are now at an all-time high, given how easy and cheap the new technologies make it to produce forged documents which not just carry threat to an individual’s respect in society or career aspirations but can also prove to be life threatening if they are placed in the wrong hands. Thus, it is very important to have mechanisms that prevent or rather make it computationally unfeasible to forge these important documents. In this paper, we present an extensive review of techniques aimed at making tamper resistant physical documents, published across last two decades. We provide an in-depth classification of the means used for securing documents in the existing literature, discuss their limitations, open areas and future insights to address the open issues and challenges.

     

Role of collective ownership and coding standards in coordinating expertise in software project teams

Software development is a complex undertaking that continues to present software project teams with numerous challenges. Software project teams are adopting extreme programming (XP) practices in order to overcome the challenges of software development in an increasingly dynamic environment. The ability to coordinate software developers' efforts is critical in such conditions. Expertise coordination has been identified as an important emergent process through which software project teams manage non-routine challenges in software development. However, the extent to which XP enables software project teams to coordinate expertise is unknown. Drawing on the agile development and expertise coordination literatures, we examine the role of collective ownership and coding standards as processes and practices that govern coordination in software project teams. We examine the relationship between collective ownership, coding standards, expertise coordination, and software project technical quality in a field study of 56 software project teams comprising 509 software developers. We found that collective ownership and coding standards play a role in improving software project technical quality. We also found that collective ownership and coding standards moderated the relationship between expertise coordination and software project technical quality, with collective ownership attenuating the relationship and coding standards strengthening the relationship. Theoretical and practical implications of the findings are discussed.     

Educational magic toys developed with augmented reality technology for early childhood education

Shaping children's experience, enhancing their imagination and affecting their behaviors, toys have great importance. Recently, toys have gained a digital characteristic and many children have tended to use them. For this reason, educational magic toys (EMT) were developed with augmented reality technology in this study. It is called as EMT because virtual objects such as story animations, 3D objects and flash animations appear on the toys. EMT has included puzzles, flash cards and match cards to teach animals, fruits, vegetables, vehicles, objects, professions, colors, numbers and shapes for average 5–6 age children in Early Childhood Education. The aim of this study is to reveal teachers' and children's opinions on EMT, to determine children's behavioral patterns and their cognitive attainment, and the relationship between them while playing EMT. Mix method was used and the sample consisted of 30 teachers and 33 children aged 5–6 in early childhood education. As data collection tools, a survey, an observation and interview form were used. This study revealed that teachers and children liked EMT activity. In addition, children interactively played with these toys but not had high cognitive attainment. From this point, we can say that these toys can be effectively used in early childhood education. However, collaborative and interactive learning with these toys should be provided. Moreover, this study will provide an important contribution, present a new educational AR application, and fill the gap in the educational technology field.     

A replicated quasi-experimental study on the influence of personality and team climate in software development

This article reports a replication of a quasi-experimental study analyzing how personality factors and team climate influence software development team effectiveness, product quality and team member satisfaction. The replication was designed on the basis of the original quasi-experimental study, both of which were run in an academic setting. In the original study, data were collected from a sample of 35 three-member developer teams. All these teams used an adaptation of extreme programming (XP) to the academic environment to develop the same software system. In the replication, the data were collected from a sample of 34 three- or four-member developer teams working on the same software project. Student teams used a common object-oriented software development paradigm to solve the set problem and applied the Unified Process. In both studies all teams were formed at random, and their members were blind to the quasi-experimental conditions and hypotheses. The replication of this empirical study aims to verify the results of the original quasi-experiment. It examines, first, whether personality factors (neuroticism, extroversion, agreeableness, openness to experience and conscientiousness) are related to the quality of the developed software and team member satisfaction and, second, whether the preferences, perceptions and preferences-perceptions fit for the four team climate factors (participative safety, support for innovation, team vision and task orientation) are related to the quality of the developed software and team member satisfaction. The results of the replication corroborate some of the findings of the original study. On the one hand, the results revealed that there is a significant correlation between the extroversion personality factor and software quality, but no significant correlation between the extroversion personality factor and team satisfaction. Also, we found that the perception of team climate where participative safety is high is related to better quality software. We observed significant relationships between the perception of the four team climate factors and team member satisfaction. Additionally, the results showed a positive relationship between software quality and teams in which the real climate perception at the end of the project is better than preferences stated by team members at the outset of the project for the participative safety factor. Finally, we found that teams where the real climate is better than the stated preferences for the team orientation factor exhibit a direct and positive relationship to team member satisfaction.     

Successful extreme programming: Fidelity to the methodology or good teamworking?

ContextDeveloping a theory of agile technology, in combination with empirical work, must include assessing its performance effects, and whether all or some of its key ingredients account for any performance advantage over traditional methods. Given the focus on teamwork, is the agile technology what really matters, or do general team factors, such as cohesion, primarily account for a team’s success? Perhaps the more specific software engineering team factors, for example the agile development method’s collective ownership and code management, are decisive.ObjectiveTo assess the contribution of agile methodology, agile-specific team methods, and general team factors in the performance of software teams.MethodWe studied 40 small-scale software development teams which used Extreme Programming (XP). We measured (1) the teams’ adherence to XP methods, (2) their use of XP-specific team practices, and (3) standard team attributes, as well as the quality of the project’s outcomes. We used Williams et al.’s (2004a) [33] Shodan measures of XP methods, and regression analysis.ResultsAll three types of variables are associated with the project’s performance. Teamworking is important but it is the XP-specific team factor (continuous integration, coding standards, and collective code ownership) that is significant. Only customer planning (release planning/planning game, customer access, short releases, and stand-up meeting) is positively related to performance. A negative relationship between foundations (automated unit tests, customer acceptance tests, test-first design, pair programming, and refactoring) is found and is moderated by craftsmanship (sustainable pace, simple design, and metaphor/system of names). Of the general team factors only cooperation is related to performance. Cooperation mediates the relationship between the XP-specific team factor and performance.ConclusionClient and team foci of the XP method are its critical active ingredients.     

Users and designers as partners - design method and tools for user participation and designer accountability within the design process

Abstract. We have found two main causes of inadequacies in a decision support system designed by us. They are, in general, the lack of direct user participation and the lack of designer accountability in the design process. In an attempt to solve the problem, we develop a new design method, the User Participation and Designer Accountability (UPDA) method. It involves users' direct manipulation of colour cards, which contain the contents of simple design charts. These cards are also made accessible to everyone involved in the design process and form the basis upon which the designer can be questioned. We have applied the UPDA method and so far the reactions are very positive.     

Achieving better usability of software supporting learning activities of large groups

Many business schools around the world offer courses to train their students in acquiring so called “soft skills”, such as working in teams for decision making or sharing information to collaboratively solve complex problems. These courses often include learning activities where students are asked to generate ideas, discuss them, rank them and select the best ones. In order to develop their IT skills, students are often asked to take advantage of available IT technologies for supporting this task. If geographical location information is prominently used to provide context information about the ideas students propose and discuss, this activity can be classified as geo-collaborative. Free software available from the web has often been used to support this kind of work, like Google Maps, for geo-referencing the ideas, the text editor of Google Drive for describing them and Twitter or Facebook to exchange messages and comments. These applications are robust and suitable for use by large groups of students engaged in a situated learning activity. In the context of a learning activity taking place in a business school in Chile, the authors observed students for four semesters collaboratively using these tools to identify ways of improving life or solving problems in certain areas of the city which have to be georeferenced on a map. They had to generate proposals, discuss them and select the ten best. Through feedback provided by students, we identified problems regaring information overload, the lack of support for collaboration and unsatisfactory usability. From these findings we derived requirements for software especially designed to support this learning activity and have a tool that offers better usability. A prototype was developed to cope with these requirements. It was used for two semesters and evaluated under the same conditions when students used free and/or standard software. The experiment yielded positive results and gave us valuable insight on how to implement main features of a system supporting learning activities for large groups that includes decision making, blogging and geo-collaboration.     

An empirical study of relationships among extreme programming engineering activities

Extreme programming (XP) is an agile software process that promotes early and quick production of working code. In this paper, we investigated the relationship among three XP engineering activities: new design, refactoring, and error fix. We found that the more the new design performed to the system the less refactoring and error fix were performed. However, the refactoring and error fix efforts did not seem to be related. We also found that the error fix effort is related to number of days spent on each story, while new design is not. The relationship between the refactoring effort and number of days spent on each story was not conclusive.     

Sound,paper and memorabilia: resources for a simpler digital photography

In this paper we reflect on a body of work to develop a simpler form of digital photography. We give three examples of ‘Less is More’ thinking in this area which are directed and inspired by naturalistic user behaviours and reactions to design ideas. Each example happens to review the place of an old technology in the new scheme of things, and challenges a technological trend in the industry. Hence, we consider the role of sound in photography to recommend audiophotographs rather than short video clips as a new media form. We look again at the role of paper in photo sharing and recommend its support and augmentation against the trend towards screen-based viewing. Finally, we consider the role of physical souvenirs and memorabilia alongside photographs, to recommend their use as story triggers and containers, in contrast to explicit multimedia presentations. The implications for simple computing are discussed. This paper originated from the International Forum ‘Less is More—Simple computing in an age of complexity’, 27–28 April 2005, Cambridge UK.