The organization of interaction design pattern languages alongside the design process

This work explores the possibility of taking the structural characteristics of approaches to interaction design as a basis for the organization of interaction design patterns. The Universal Model of the User Interface (Baxley, 2003) is seen as well suited to this; however, in order to cover the full range of interaction design patterns the model had to be extended slightly. Four existing collections of interaction design patterns have been selected for an analysis in which the patterns have been mapped onto the extended model. The conclusion from this analysis is that the use of the model supports the process of building a pattern language, because it is predictive and helps to complete the language. If several pattern writers were to adopt the model, a new level of synergy could be attained among these pattern efforts. A concluding vision would be that patterns could be transferred freely between pattern collections to make them as complete as possible.     

网络媒体的视觉传达设计研究

基于网络媒体的视觉传达设计是一个崭新的领域,同时也是属于艺术设计创新领域的范畴。随着互联网技术的飞速发展,视觉传达设计正日渐向立体化、交互性偏移,这对传统设计者而言是在风格、手法和思维上的挑战,同时也是这一领域的重大变革。本文将立足于新媒体领域,对网络媒体的视觉传达设计的特征和需求进行分析,结合多方面的艺术表现要素和具体项目实践内容,提出相关的建议和对策。     

Learning with web-based interactive objects: An investigation into student perceptions of effectiveness

In its efforts to continue the modernization of its curriculum, the Faculty of Dentistry at the University of Toronto has developed a series of web-based interactive learning applications. This article presents the production cycle of these new interactive learning objects and the preliminary study conducted to measure the students’ perception of the objects’ effectiveness for learning. Three applications are described in detail in this article, namely: Panoramic Radiography: Principles and Interpretation, Gross Human Anatomy 3D Atlas and Restorative Dentistry: Virtual and Interactive Cavity Preparation. Each of these applications introduces unique elements of interactivity with the learning content, specifically designed to address hard-to-grasp concepts in their respective dental disciplines. The results of a student survey conducted post-deployment suggest that the visual and interactive features embedded in the three applications have the potential to induce positive outcomes in mediating the students’ conceptualization of difficult theoretical notions.     

Defining the abstract syntax of visual languages with advanced graph grammars—A case study based on behavior trees

Diagrammatic visual languages can increase the ability of engineers to model and understand complex systems. However, to effectively use visual models, the syntax and semantics of these languages should be defined precisely. Since most diagrammatic visual models that are currently used to specify systems can be described as (directed) typed graphs, graph grammars have been identified as a suitable formalism to describe the abstract syntax of visual modeling languages. In this article, we investigate how advanced graph-transformation techniques, such as conditional, structure-generic and type-generic graph-transformation rules, can help to improve and simplify the specification of the abstract syntax of a visual modeling language. To demonstrate the practicability of an approach that unifies these advanced graph-transformation techniques, we define the abstract syntax of behavior trees (BTs), a graphical specification language for functional requirements. Additionally, we provide a translational semantics of BTs by formalizing a translation scheme to the input language of the SAL model checking tool for each of the graph-transformation rules.     

Automated verification of design patterns: A case study

Representing design decisions for complex software systems, tracing them to code, and enforcing them throughout the lifecycle are pressing concerns for software architects and developers. To be of practical use, specification and modeling languages for software design need to combine rigor with abstraction and simplicity, and be supported by automated design verification tools that require minimal human intervention. This paper examines closely the use of the visual language of Codecharts for representing design decisions and demonstrate the process of verifying the conformance of a program to the chart. We explicate the abstract semantics of segments of the Java package java.awt as a finite structures, specify the Composite design pattern as a Codechart and unpack it as a set of formulas, and prove that the structure representing the program satisfies the formulas. We also describe a set of tools for modeling design patterns with Codecharts and for verifying the conformance of native (plain) Java programs to the charts.     

The influence of the instruction of visual design principles on improving pre-service teachers’ visual literacy

This study investigated whether the instruction of visual design principles had an influence on pre-service teachers’ perception and analysis (interpretation) of visual materials. In addition, the relationships between pre-service teachers’ visual intelligence and their perception and analysis (interpretation) of visual materials were also explored. Participants were 86 pre-service teachers who took a one-credit required educational technology course at a mid-western university in the United States. Some participants were absent in the weeks when data were collected, resulting in a total of 59 responses included in data analysis. Findings implied that the instruction of visual design principles could possibly improve pre-service teachers’ visual literacy. Suggestions for future research were discussed.     

The effects of visual metaphor and cognitive style for mental modeling in a hypermedia-based environment

With the exponential growth of Internet technology, the notion of users’ cognition when navigating such a vast information space has gained prominence. Studies suggest that metaphors can serve as effective tools to scaffold users’ mental modeling processes. However, how users conceive of the metaphorical aid (as opposed to simply how they perceive it) remains questionable. Cognitive style, or the user’s preferred way of information processing, has thus been posited as a possible factor affecting the success of the metaphorical approach in a hypermedia environment.

This study explores the effects of visual metaphors and cognitive styles on users’ learning performances in terms of structural knowledge and feelings of disorientation. The results indicate that a visual metaphor could improve the quality of mental formation, yet simultaneously increase users’ mental load during navigation. In addition, cognitive style is a crucial factor that can significantly affect users’ learning performance.     

The complex role of perceptual organization in visual display design theory

Two experiments were performed to test and extend the current ‘emergent features’ approach to display design for dynamic failure detection tasks. It was predicted that a display whose emergent features were well-mapped to goal-relevant task invariants would lead to better failure detection performance than either of two alternative displays. Contrary to prediction, Experiment 1 showed no differences in failure detection speed or accuracy across displays. The reason for this may have been that subjects did not discover the mapping between the mathematical properties of the task and the emergent feature, so in Experiment 2 subjects were explicitly instructed about the mapping and were advised on how to use the display geometry to help their performance. A significant difference in failure detection speed emerged, but the display supporting fastest performance was not the one with the well-mapped emergent feature. These results suggest that alternative perceptual organizational factors were at work which overpowered the intended effect. The results also underscore the difficulty of developing a theory of display design, and their impact on current theories is outlined.     

EVoIP: Energy efficient voice over IP privacy

Due to the convergence of telecommunication technologies and pervasive computing, voice is increasingly being transmitted over IP networks, in what is commonly known as Voice over IP (VoIP). Despite many advantages offered by this technology, VoIP applications inherit many challenging characteristics from the underlying IP network related to quality of service and security concerns. Traditional ways to secure data over IP networks have negative effects on real-time applications and on power consumption, which is scarce in power-constrained handheld devices. In this work, a new codec-independent Energy Efficient Voice over IP Privacy (E²VoIP²) algorithm is devised to limit the overhead of the encryption process, without compromising the end-to-end confidentiality of the conversation. The design takes advantage of VoIP stream characteristics to encrypt selected packets using a secure algorithm, while relaxing the encryption procedure in-between these packets. We evaluated experimentally the difficulty of conducting known plaintext attacks on VoIP by demonstrating that a sound recorded simultaneously by different sources results in apparently random encoded files. Regarding E²VoIP², experimental and simulation results show a substantial improvement in terms of the number of CPU cycles which results in a reduction of latency and a reduction in consumed power with respect to that of the SRTP. In addition, the proposed method is flexible in terms of the balance between security and power consumption.     

P-selective sets,tally languages,and the behavior of polynomial time reducibilities onNP

The notion ofp-selective sets, and tally languages, are used to study polynomial time reducibilities onNP. P-selectivity has the property that a setA belongs to the classP if and only if both _m ^p A andA isp-selective. We prove that for every tally language set inNP there exists a polynomial time equivalent set inNP that isp-selective. From this result it follows that if NEXT DEXT, then polynomial time Turing and many-one reducibilities differ onNP. This research was supported in part by the National Science Foundation under grant MCS 77-23493     

Hybrid methodology for data warehouse conceptual design by UML schemas

Context

Data warehouse conceptual design is based on the metaphor of the cube, which can be derived from either requirement-driven or data-driven methodologies. Each methodology has its own advantages. The first allows designers to obtain a conceptual schema very close to the user needs but it may be not supported by the effective data availability. On the contrary, the second ensures a perfect traceability and consistence with the data sources—in fact, it guarantees the presence of data to be used in analytical processing—but does not preserve from missing business user needs. To face this issue, the necessity emerged in the last years to define hybrid methodologies for conceptual design.

Objective

The objective of the paper is to use a hybrid methodology based on different multidimensional models in order to gather all advantages of each of them.

Method

The proposed methodology integrates the requirement-driven strategy with the data-driven one, in that order, possibly performing alterations of functional dependencies on UML multidimensional schemas reconciled with data sources.

Results

As case study, we illustrate how our methodology can be applied to the university environment. Furthermore, we evaluate quantitatively the benefits of this methodology by comparing it with some popular and conventional methodologies.

Conclusion

In conclusion, we highlight how the hybrid methodology improves the conceptual schema quality. Finally, we outline our present work devoted to introduce automatic design techniques in the methodology on the basis of the logical programming.     

Optimal periodic feedback design for continuous-time LTI systems with constrained control structure

This paper aims to design a high-performance controller with any predefined structure for continuous-time LTI systems. The control law employed is the generalized sampled-data hold function (GSHF), which can have any special form, e.g. polynomial, exponential, piecewise constant, etc. The GSHF is first written as a linear combination of a set of basis functions obtained in accordance with its desired form and structure. The objective is to find the coefficients of this linear combination, such that a prespecified linear-quadratic performance index is minimized. A necessary and sufficient condition for the existence of such GSHF is first obtained in the form of matrix inequality, which can be solved by using the existing methods to obtain a set of stabilizing initial values for the coefficients or to conclude the non-existence of such structurally constrained GSHF. An efficient algorithm is then presented to compute the optimal coefficients from their initial values, so that the performance index is minimized. The paper utilizes the latest developments in the area of sum-of-square polynomials. The effectiveness of the proposed method is demonstrated in two numerical examples.     

Interpolating G Bézier surfaces over irregular curve networks for ship hull design

We propose a local method of constructing piecewise G¹ Bézier patches to span an irregular curve network, without modifying the given curves at odd- and 4-valent node points. Topologically irregular regions of the network are approximated by implicit surfaces, which are used to generate split curves, which subdivide the regions into triangular and/or rectangular sub-regions. The subdivided regions are then interpolated with Bézier patches. We analyze various singular cases of the G¹ condition that is to be met by the interpolation and propose a new G¹ continuity condition using linear and quartic scalar weight functions. Using this condition, a curve network can be interpolated without modification at 4-valent nodes with two collinear tangent vectors, even in the presence of singularities. We demonstrate our approach in a ship hull.     

Convergence analysis for reduced-order adaptive controller design of uncertain SISO linear systems with noisy output measurements

We consider in this article a class of uncertain SISO linear systems that are subject to system and measurement noises. Reduced-order adaptive controller designs have been proposed before for such systems by the authors and stability analysis of the closed-loop systems has been established. Here we analyse, further, the robustness properties for these reduced-order adaptive control systems by providing detailed convergence analysis results for the key closed-loop signals and parameter estimates. We rigorously prove that, whenever the exogenous disturbance input is of finite energy and bounded, and the reference trajectory and its derivatives up to rth order are bounded, r being the relative degree of the transfer function of the true system, a set of signals, including the tracking error, the estimation error between the system output and its estimate, the projection signal, are of finite energy and converge to zero; and the system states and their estimates exhibit asymptotic behaviours with certain formats. With an additional persistency of excitation condition, it is also proved that the estimate and the worst-case estimate of the state vector asymptotically track the actual state vector; and the estimate and the worst-case estimate of the unknown parameter vector converge to the true value. A numerical example is given to illustrate the theoretical findings.     

Modelling co-operation in the design of knowledge production systems: The Made In'Coop method

This paper presents the latest developments of the MadeIn 'Coop method for modelling the human-machine and human-human co-operation process, and an application of this method for the design of a more co-operative version of the C³I System CHEOPS. We first consider that the design of software systems for organizations is tied more and more to the perspective of compound Knowledge Production Systems that link humans and machines engaged in a co-operative problem solving process. After exposing the four principles upon which MadeIn 'Coop rests for modelling co-operation, we present an artificial problem solving dialogue between CHEOPS and its users. Consistent with the Group Cognitive Processes Theory framework, we propose a dialogue analysis according to two complimentary points of view: the Collective Problem Solving model, and the Coordination model. This analysis should help system designers to identify new system functionalities to assist problem solving.(C³I) Command Control Communication Intelligence Systems     

G2连续的低次避障代数样条曲线

为便于机器人在避障时能高速前进,把整体G2连续的低次避障曲线从参数形式拓展到代数样条形式上。首先,对导向折线段中除去首末线段的其他线段插入中点,以生成一组控制多边形;然后,根据各控制多边形和与之对应的障碍物,得到既能使曲线规避所有障碍物,又能使曲线在整体上保持G2连续的形状因子。低次避障代数样条曲线不仅能够直接得到与给定点之间的位置关系,还具有次数低、连续阶高、计算简单、保形性好和便于控制的优点。曲线在次数为3时更是具有局部可调性,其在设计时的灵活度得以增加。     

Optimal and control of hybrid multirate systems

The problem of using a synchronous multirate digital controller for a continuous-time plant is considered. The performance objectives considered are the H^∞ and the H² norms of the periodically time-varying continuous-time input-output behavior of the closed loop system. A continuous-time lifting technique is used to solve these hybrid sampled-data problems. This approach yields equivalent purely discrete-time problems while preserving the multirate causality of the systems. The later problems can then be solved using known techniques.     

Safe design of high-performance embedded systems in an MDE framework

In this paper, we use the UML MARTE profile to model high-performance embedded systems (HPES) in the GASPARD2 framework. We address the design correctness issue on the UML model by using the formal validation tools associated with synchronous languages, i.e., the SIGALI model checker, etc. This modeling and validation approach benefits from the advantages of UML as a standard, and from the number of validation tools built around synchronous languages. In our context, model transformations act as a bridge between UML and the chosen validation technologies. They are implemented according to a model-driven engineering approach. The modeling and validation are illustrated using the multimedia functionality of a new-generation cellular phone.     

An H-minimax approach to the design of robust control systems

A realistic feedback design problem is posed based on the minimization of a weighted combination of the sensitivity and complementary sensitivity matrices. A solution is obtained which makes use of the recently proposed methods for minimizing the sensitivity function alone.