On keys' meanings and modes: the impact of different key solutions on children's efficiency using a mobile phone

The present study investigates the impact of different key solutions of mobile phones on users' effectiveness and efficiency using the devices. In the first experiment, 36 children (9 – 14 years) and in the second experiment 45 young adults (19 – 33 years) completed four common phone tasks twice consecutively on three simulated phones that had identical menus, but different key solutions. An approach was undertaken to quantify the complexity of keys in three models, incorporating different factors contributing to the keys' complexity (number of key options, number of modes and number of modes with a semantically dissimilar meaning), in order to predict users' performance decrements. As a further main factor, the degree of the users' locus of control (LOC) was measured and interactions with performance outcomes were studied. As dependent measures, the number of inefficient keystrokes, the number of tasks solved and the processing time were determined. Results showed a significant effect of control key solutions on users' efficiency and effectiveness for both children and young adults. Moreover, children's LOC values significantly interacted with performance: children with low LOC values showed the lowest performance and no learnability, especially when using keys with a high complexity. From the three factors contributing to the complexity of keys, keys exerting different functions with semantically inconsistent meanings had the worst effect on performance. It is concluded that in mobile user interface design keys with semantically inconsistent meanings should be generally avoided.     

Children using cellular phones: the effects of shortcomings in user interface design

Differences in cellular phones' complexity and their impact on children's performance are under study in this experiment. Twenty children (age 9-14 years) solved tasks on two phones that were simulated according to existing models on a PC with a touch screen, holding constant display size, fonts, and colors. Actions were logged and analyzed regarding execution time, detour steps, and specific errors. Results show that children using the Siemens C35i with 25% higher complexity (with regard to number of required production rules) spent double the time solving tasks and undertook three times as many detour steps as children using the less complex Nokia 3210. A detailed analysis of user actions revealed that the number of production rules to be learned fails to account for most difficulties. Instead, ambiguous naming, poor categorization of functions, and unclear functionality of keys undermined performance. Actual or potential applications of this research include guidelines to improve the usability of all devices with small displays and hierarchical menu structures, such as cellular phones.     

The influence of user expertise and phone complexity on performance, ease of use and learnability of different mobile phones

The study focuses on usability, ease of use and learnability of three different mobile phones (Nokia 3210, Siemens C35i, Motorola P7389). The first independent variable refers to the complexity of the menu (depth/breadth of the menu tree) and navigation keys (number/functionality). The Nokia phone had the lowest and the Motorola the highest complexity, with the Siemens phone ranging between them. The second independent variable was user expertise: 30 novices and 30 experts solved six telephone tasks. In order to assess effects of learnability, tasks were presented twice. Differences between the mobile phones regarding effectiveness, efficiency and learnability were found: The best performance was shown by Nokia users. The remaining two phones did not differ significantly, although the most complex phone was superior to the phone of medium complexity which had the lowest performance. Moreover, an effect of expertise was confirmed, though suboptimal interfaces were identified as lessening the advantage of expertise. Specific weaknesses of the tested phones are discussed.     

The influence of user expertise and phone complexity on performance,ease of use and learnability of different mobile phones

The study focuses on usability, ease of use and learnability of three different mobile phones (Nokia 3210, Siemens C35i, Motorola P7389). The first independent variable refers to the complexity of the menu (depth/breadth of the menu tree) and navigation keys (number/functionality). The Nokia phone had the lowest and the Motorola the highest complexity, with the Siemens phone ranging between them. The second independent variable was user expertise: 30 novices and 30 experts solved six telephone tasks. In order to assess effects of learnability, tasks were presented twice. Differences between the mobile phones regarding effectiveness, efficiency and learnability were found: The best performance was shown by Nokia users. The remaining two phones did not differ significantly, although the most complex phone was superior to the phone of medium complexity which had the lowest performance. Moreover, an effect of expertise was confirmed, though suboptimal interfaces were identified as lessening the advantage of expertise. Specific weaknesses of the tested phones are discussed.     

Designing the user interface of the computer-based speech training system ARTUR based on early user tests

This study has been performed in order to evaluate a prototype for the human - computer interface of a computer-based speech training aid named ARTUR. The main feature of the aid is that it can give suggestions on how to improve articulations. Two user groups were involved: three children aged 9 - 14 with extensive experience of speech training with therapists and computers, and three children aged 6, with little or no prior experience of computer-based speech training. All children had general language disorders. The study indicates that the present interface is usable without prior training or instructions, even for the younger children, but that more motivational factors should be introduced. The granularity of the mesh that classifies mispronunciations was satisfactory, but the flexibility and level of detail of the feedback should be developed further.     

Book Review

In this experiment, older and younger novice mobile phone users were examined when using handsets of different complexity. The independent variables were user age (young: 20 – 35 years; old: 50 – 64 years) and cognitive complexity of two mobile phones (Nokia 3210; Siemens C35i). The cognitive complexity of the phones was defined by the number of production rules applied when processing the four experimental tasks. Dependent variables were effectiveness and efficiency as taken from user protocols and the reported ease of use. The less complex phone (Nokia) performed significantly better than the complex one (Siemens). However, the benefit from the lower complexity was much larger than theoretically predicted. Thus, defining cognitive complexity of technical devices by the number of production rules does not account for the real difficulties which users experience. Older users had a lower navigation performance than younger users, however their performance matched younger users' when using mobiles with low complexity.     

Website task performance by older adults

The present study examined influences of fluid intelligence and website experience on a website task by 99 community-dwelling older adults (41 males, 58 females, age range 58 - 90 years) who were screened for visual acuity and major health problems. They were divided into three groups, dependent on their prior website experience (19 with no prior website experience, 55 with low website experience and 25 with high website experience). Perpendicular to this, the participants were divided into low- and high-fluid intelligence groups and into young - old and old - old age groups. Participants performed a website information retrieval task using three health information websites. Performance was assessed by the time taken to retrieve target information. Overall, the three websites significantly differed in the time taken to locate the target information. The website task performance was not significantly influenced by fluid intelligence score or age, but there was a significant influence by prior website experience.     

Examining the impact of cell phone conversations on driving using meta-analytic techniques

OBJECTIVE: The performance costs associated with cell phone use while driving were assessed meta-analytically using standardized measures of effect size along five dimensions. BACKGROUND: There have been many studies on the impact of cell phone use on driving, showing some mixed findings. METHODS: Twenty-three studies (contributing 47 analysis entries) met the appropriate conditions for the meta-analysis. The statistical results from each of these studies were converted into effect sizes and combined in the meta-analysis. RESULTS: Overall, there were clear costs to driving performance when drivers were engaged in cell phone conversations. However, subsequent analyses indicated that these costs were borne primarily by reaction time tasks, with far smaller costs associated with tracking (lane-keeping) performance. Hands-free and handheld phones revealed similar patterns of results for both measures of performance. Conversation tasks tended to show greater costs than did information-processing tasks (e.g., word games). There was a similar pattern of results for passenger and remote (cell phone) conversations. Finally, there were some small differences between simulator and field studies, though both exhibited costs in performance for cell phone use. CONCLUSION: We suggest that (a) there are significant costs to driver reactions to external hazards or events associated with cell phone use, (b) hands-free cell phones do not eliminate or substantially reduce these costs, and (c) different research methodologies or performance measures may underestimate these costs. APPLICATION: Potential applications of this research include the assessment of performance costs attributable to different types of cell phones, cell phone conversations, experimental measures, or methodologies.     

基于IBE技术的学分制管理系统安全解决方案

针对目前学分制管理系统存在的数据存储不加密、数据传输不安全、身份验证不严格等问题,分析了用PKI技术解决这些问题的不足,提出了一种基于身份加密技术的改进方案。采用表示用户身份的任意字符串作为公钥、严格验证用户身份、对关键数据进行数字签名、网络传输使用安全连接等方法,保证了数据存储、传输等过程的机密性、完整性、可用性和不可抵赖性,克服了传统PKI技术产生、存储和管理公钥麻烦、系统实现复杂、成本高、效率低等缺点。理论分析和实验结果表明该方法是学分制管理系统安全问题的较好解决方案。     

Comparison of 3D and 2D menus for cell phones

Few prior studies have directly compared 3D and 2D menus for cell phones. Because the technology available for cell phone interfaces has changed in recent years, interface guidelines for cell phones need to be re-evaluated, especially with regard to the use of 3D interfaces. In the present study, we first compared performance of tasks for menus with different breadths using three 3D menus (revolving stage, 3D carousel, and collapsible cylindrical tree) shown on the small display screen of an iPhone® simulator. Performance was best with the revolving stage menu, and there was a nonsignificant tendency for it to be rated as preferred by the participants. Then, we compared the 3D revolving stage menu to a 2D overview menu, for tasks of different complexity and menus of different breadths, on an actual iPhone. The 3D menu was preferred by users at high breadth levels, and the 2D menu showed better performance than the 3D menu with low memory load. From the results, recommendations for the design of menus for small displays were developed.     

MASHED: Security and privacy-aware mutual authentication scheme for heterogeneous and distributed mobile cloud computing services

ABSTRACT

Rapid development in mobile devices and cloud computing technologies has increased the number of mobile services from different vendors on the cloud platform. However, users of these services are facing different security and access control challenges due to the nonexistence of security solutions capable of providing secure access to these services, which are from different vendors, using a single key. An effective security solution for heterogeneous Mobile Cloud Computing (MCC) services should be able to guarantee confidentiality and integrity through single key-based authentication scheme. Meanwhile, a few of the existing authentication schemes for MCC services require different keys to access different services from different vendors on a cloud platform, thus increases complexity and overhead incurred through generation and storage of different keys for different services.

In this paper, an efficient mutual authentication scheme for accessing heterogeneous MCC services is proposed. The proposed scheme combines the user’s voice signature with cryptography operations to evolve efficient mutual authentication scheme devoid of key escrow problem and allows authorized users to use single key to access the heterogeneous MCC services at a reduced cost.     

一种新的私钥安全存取方案

安全的私钥存取机制是构建可靠PKI系统的关键问题之一。从对私钥拥有者的强身份认证和保护私钥存储机密性这两个角度出发,提出了一种新的基于GQ(GuillouQuisquater)零知识身份认证体制的私钥安全存取方案。该方案将端实体的私钥以密文形式存放在CA中。当端实体使用私钥时,系统采用双因素认证技术(GQ体制和秘密值h)验证端实体身份, 可以有效抵御认证过程中潜在的各种攻击,同时避免信息泄漏。此外,端实体首次使用私钥后,重新生成保护密钥,利用该保护密钥对私钥加密,再将密文传回CA, 从而最大限度地确保了私钥传输和存储的机密性。     

Concepts in formal and linguistic ontologies

This study considers aspects of conceptualization in linguistic ontologies, i.e., ontologies where the concepts are closely related to the meanings of linguistic units and domain terms. The main difficulties regard the complexity of splitting sets of semantically similar word meanings into classes of discrete conceptual units.     

基于Symbian的情景数据存储管理

随着智能手机所集成的传感器数量和用户对手机依赖性的增加,应用程序通过手机所能采集的关于用户行为或使用场景相关的数据越来越多。如何充分利用从手机端搜集的情景数据集,从中挖掘或分析出用户的习惯,从而为用户提供更好的服务,得到了相关研究人员和程序开发者的重视,请求这些数据的相关应用程序数目也不断增加。针对情景数据的存储没有一个统一的管理方案的问题,此处提出了一种统一的、基于Symbian S60 V5平台的情景处理框架的情景数据存储方案。它不但能够为应用程序提供统一的数据存储方案,提高了软件的模块化,同时能够有效地解决同一类数据被多个应用程序存储造成的数据冗余问题。     

基于用户兴趣语义的视频关键帧提取

目前,视频关键信息提取技术主要集中于根据视频低层特征进行关键帧的提取,忽略了与用户兴趣相关的语义信息。对视频进行语义建模需收集大量已标注的视频训练样本,费时费力。为缓解这一问题,使用大量互联网图像数据构建基于用户兴趣的语义模型,这些图像数据内容丰富、同时涵盖大量事件信息;然而,从互联网获取的图像知识多样且常伴随图像噪声,使用蛮力迁移将大幅影响视频最终提取效果,提出使用近义词联合权重模型衡量互联网中存在差异但语义相近的图像组,并利用这些图像组构建语义模型。通过联合权重学习获取语义权重,每一图像组在知识迁移中所起的作用由权重值决定。使用来自不同视频网站的多段视频对所提方法进行验证,实验结果表明对用户感兴趣的内容进行联合权重语义建模能更加全面、准确地获取信息,从而有效指导视频关键帧提取。     

Possible and certain keys for SQL

Driven by the dominance of the relational model and the requirements of modern applications, we revisit the fundamental notion of a key in relational databases with NULL. In SQL, primary key columns are NOT NULL, and UNIQUE constraints guarantee uniqueness only for tuples without NULL. We investigate the notions of possible and certain keys, which are keys that hold in some or all possible worlds that originate from an SQL table, respectively. Possible keys coincide with UNIQUE, thus providing a semantics for their syntactic definition in the SQL standard. Certain keys extend primary keys to include NULL columns and can uniquely identify entities whenever feasible, while primary keys may not. In addition to basic characterization, axiomatization, discovery, and extremal combinatorics problems, we investigate the existence and construction of Armstrong tables, and describe an indexing scheme for enforcing certain keys. Our experiments show that certain keys with NULLs occur in real-world data, and related computational problems can be solved efficiently. Certain keys are therefore semantically well founded and able to meet Codd’s entity integrity rule while handling high volumes of incomplete data from different formats.     

JTable内中文输入的一种解决方案

为了能在JTable表格中方便地输入中文数据,创造性地研究出某些特殊的能在中文输入法下直接启动数据输入的键盘键位。利用JAVA中机器人技术完成特定的动作,提高了用户输入的效率,也丰富了JAVA机器人技术的应用。     

Factors influencing feature usage in work-related communication

Two studies are presented. The first aimed to identify possible barriers to the uptake and use of commonly available telephony features and to determine whether greater knowledge of features/access codes and availability of user manuals could increase feature usage under certain conditions. Results showed that feature-usage patterns were not affected by any of the manipulations, but that they were determined by specific job demands. Using Constantine and Lockwood's (1999) conceptualization of user roles, a method to support feature bundling decisions for specific target markets was developed and tested in the second study. The method - Strategic User Needs Analysis (SUNA) - was shown to yield a useful balance between high- and low-level information about selected roles. SUNA provided sufficient information to distinguish between PDA feature usage patterns of two similar target user groups as well as to suggest additional features each of the two target groups would find useful. The development of SUNA and observational findings of actual PDA usage are reported.     

Computationally Efficient Distributed and Delegated Certification

Certification in public key cryptographic applications concerns the involvement of a CA (Certifying Agent) in approving the validity of users' public keys. Distributed certification pertains to the case where several CAs are involved in issuing certificates. This also includes the case of multi-attribute certification, where different CAs approve different user's attributes. In delegated certification, agents transfer certificate issuing authority in hierarchical chain. Distributed, multi-attribute and delegated certification techniques having a low computational complexity are presented in this paper. It is shown how multiplicity aspects of the various applications are mapped into a multiplied exponents mathematical implementation of the form Pi_i=1 ^m A_i ^bi mod p, which is essentially equivalent to a single exponentiation for a moderate m. A fundamental feature of the presented procedures pertains to implementing distributed/multi-attribute certification by referring to any desired subset of participating CAs.     

一种支持共享的高可用数据库加密机制

加密数据库可以保证数据在数据库存储期间的机密性,但往往难以很好地支持多用户的共享访问,难以保证良好的可用性及易用性。文章在基于字段加密的前提下,提出了一种由数据密钥对敏感数据进行加密保护,由数据库用户公钥对数据密钥进行加密保护,最终由数据库用户口令对用户私钥进行加密保护的完整数据库加密机制。据此理论建立的加密数据库模型既可以保证数据的安全性,也支持对加密信息的共享访问,在可用性、易用性方面也比以往系统有明显增强。