Design of phononic materials/structures for surface wave devices using topology optimization

We develop a topology optimization approach to design two- and three-dimensional phononic (elastic) materials, focusing primarily on surface wave filters and waveguides. These utilize propagation modes that transmit elastic waves where the energy is contained near a free surface of a material. The design of surface wave devices is particularly attractive given recent advances in nano- and micromanufacturing processes, such as thin-film deposition, etching, and lithography, which make it possible to precisely place thin film materials on a substrate with submicron feature resolution. We apply our topology optimization approach to a series of three problems where the layout of two materials (silicon and aluminum) is sought to achieve a prescribed objective: (1) a grating to filter bulk waves of a prescribed frequency in two and three dimensions, (2) a surface wave device that uses a patterned thin film to filter waves of a single or range of frequencies, and (3) a fully three-dimensional structure to guide a wave generated by a harmonic input on a free surface to a specified output port on the surface. From the first to the third example, the resulting topologies increase in sophistication. The results demonstrate the power and promise of our computational framework to design sophisticated surface wave devices.     

Ordering Method and Empirical Study on Multiple Factor Sensitivity of Group Social Attitudes Based on Entropy Theory

When studying the various factors affecting a group’s social attitudes, minor changes in a factor will easily cause changes to other factors due to their association and relevance to each other; therefore, such a factor is more sensitive, although there is a difference between sensitivity and importance. In order to comprehensively learn about the influence of multiple factors, explorations based on entropy theory have been conducted to determine the sensitivity of each factor, to specify the difference between the frequency and sensitivity priority of entropy theory, and to provide a method, a way of thinking, and a detailed basis for the resolution of actual problems.     

Voices that cannot be heard: Can shyness explain how we communicate on Facebook versus face-to-face?

Social networking sites have gained popularity among all populations, especially young adults. Personality traits were found to be predictive of how individuals use social media. Therefore, this study sought to examine the association between shyness and self-disclosure to a Facebook friend as well as self-disclosure to a face-to-face friend. Two studies were conducted. The first study tested how shyness and social loneliness are related to self-disclosure to a Facebook friend to whom an individual talks most often. The second, follow-up study tested how shyness is related to self-disclosure to a Facebook friend to whom a person speaks to only though Facebook, and also to a face-to-face friend to whom the participants talk only face-to-face and never through Facebook. Participants were college students from a large research university in the United States. Study 1 found a negative association between shyness and self-disclosure to a Facebook friend. Study 2 found a negative association between shyness and self-disclosure to a face-to-face friend. The theoretical implications and limitations are discussed.     

Using machine-learning methods for musical style modeling

The ability to construct a musical theory from examples presents a great intellectual challenge that, if successfully met, could foster a range of new creative applications. Inspired by this challenge, we sought to apply machine-learning methods to the problem of musical style modeling. Our work so far has produced examples of musical generation and applications to a computer-aided composition system. Machine learning consists of deriving a mathematical model, such as a set of stochastic rules, from a set of musical examples. The act of musical composition involves a highly structured mental process. Although it is complex and difficult to formalize, it is clearly far from being a random activity. Our research seeks to capture some of the regularity apparent in the composition process by using statistical and information theoretic tools to analyze musical pieces. The resulting models can be used for inference and prediction and, to a certain extent, to generate new works that imitate the style of the great masters.     

A scalable interest-oriented peer-to-peer pub/sub network

There has been a big challenge in structured peer-to-peer overlay network research area. Generally, a structured overlay network involves nodes evenly or based on their resource availabilities, and gathers nodes?? resources to achieve some bigger tasks. The challenge here is to gather resources based on nodes?? interests, and only interested nodes are involved in a certain task. Toward this challenge, we propose a new scheme to a peer-to-peer publish/subscribe network. Publish/subscribe represents a new paradigm for distributed content delivery. It provides an alternative to address-based communication due to its ability to decouple communication between the source and the destination. We propose a Bloom filter based mapping scheme to map IDs to nodes?? interests in addition to new interest proximity metric to forward events and to build nodes?? routing tables. We also propose a new approach called ??shared interest approach?? for network discovery. To evaluate the algorithms proposed in this work, we conducted simulations in both static and dynamic settings, and found a low false positive rate. We also discuss about a well-known application called Twitter, and show how our scheme would work in a real environment.     

Solidworks在铸造模型设计制造过程中的应用

长期以来,铸造用模的制造一直沿袭着零件图→铸造工艺图→模块设计放样→制造组合这一程序,制造周期长,成为新产品开发的瓶颈。我们应用计算机三维软件Solidworks将产品图纸转化为电子图形,然后结合铸造工艺参数直接编辑修正成放样图,实现了产品设计与模型制造交叉作业、相互验证,大大加快了模型制造的进度,提高了模型质量。     

A repairable queueing model with two-phase service,start-up times and retrial customers

A repairable queueing model with a two-phase service in succession, provided by a single server, is investigated. Customers arrive in a single ordinary queue and after the completion of the first phase service, either proceed to the second phase or join a retrial box from where they retry, after a random amount of time and independently of the other customers in orbit, to find a position for service in the second phase. Moreover, the server is subject to breakdowns and repairs in both phases, while a start-up time is needed in order to start serving a retrial customer. When the server, upon a service or a repair completion finds no customers waiting to be served, he departs for a single vacation of an arbitrarily distributed length. The arrival process is assumed to be Poisson and all service and repair times are arbitrarily distributed. For such a system the stability conditions and steady state analysis are investigated. Numerical results are finally obtained and used to investigate system performance.     

A network infrastructure for IP mobility support in metropolitan areas

The original design of the Internet and its underlying protocols did not anticipate users to be mobile. With the growing interest in supporting mobile users and mobile computing, a great deal of work is taking place to solve this problem. For a solution to be practical, it has to integrate easily with existing Internet infrastructure and protocols, and offer an adequate migration path toward what might represent the ultimate solution. In that respect, the solution has to be incrementally scalable to handle a large number of mobile users and wide geographical scopes, and well performing so as to support all application requirements including voice and video communications and a wide range of mobility speeds. In this paper, we present a survey of the state-of-the-art and propose a scalable infrastructure to support mobility in Internet protocol networks. In that respect, we exploit local area network (LAN) technologies to create the network infrastructure necessary to offer connectivity to mobile users across any geographical area (building, campus and metropolis). The intrinsic properties of LAN technologies and their underlying protocols, namely flat address space, transparent learning and low complexity renders this solution particularly cost effective for supporting user mobility. In particular, we propose a network topology and a set of protocols that render the infrastructure scalable to a large geographical area and many users.     

Postural analysis of paramedics simulating frequently performed strenuous work tasks

Paramedics who perform emergency rescue functions are highly susceptible to musculoskeletal injuries. Through an interview and survey process firefighters, many of whom are cross-trained paramedics in a consortium of 14 suburban fire departments, identified and rated tasks that were perceived to be both strenuous and frequently performed. The objective of the current study was to describe the working postures and the forces applied as firefighter/paramedics (FF/Ps) simulated specific roles within the following tasks identified by the survey: (1) transferring a patient from a bed to a stretcher using bedsheets, (2) transferring a patient from the ambulance stretcher to a hospital gurney, (3) carrying a victim down a set of stairs and around a landing using a stairchair, (4) carrying a victim down a set of stairs and around a landing using a backboard, and (5) carrying a victim down a set of stairs using a stretcher. Ten two-person teams of FF/Ps participated and were videotaped to obtain postural data for the upper and lower extremities as they performed each role in the simulated two-person tasks. Trunk postures were obtained using lumbar motion monitors. Static hand forces were estimated using a hand-held dynamometer at the most physically demanding points for each role within each task. The postural and force data were averaged across subjects performing identical roles to quantify the postures assumed by the FF/Ps at the most strenuous moments during task performance. Based on these analyses we concluded that: (1) when transferring victims from a bed to a stretcher the FF/P on the bed was able to maintain an upright and more stable posture by standing as opposed to kneeling, (2) an interface board should be used to reduce the frictional forces when transferring victims from a bed to a stretcher or from a stretcher to a gurney, thereby reducing the need to lift the victim with flexed torsos and/or shoulders, and (3) equipment and training that encourages the FF/P in the leader role to walk facing forward during victim transport, especially when descending stairs, potentially results in safer transit.     

Semantic constraint specification and verification of ebXML business process specifications

Electronic Business using eXtensible Markup Language (ebXML) Business Process Specification Schema (BPSS) supports the specification of the set of elements required to configure a runtime system in order to execute a set of ebXML business transactions. The BPSS is available in two stand-alone representations; a UML version and an XML version. Due to the limitations of UML notations and XML syntax, however, the current ebXML BPSS specification is insufficient to formally specify semantic constraints of modeling elements. In this study, we propose a classification scheme for BPSS semantic constraints, and describe how to represent those semantic constraints formally using Object Constraint Language. As a way to verify a particular Business Process Specification (BPS) with formal semantic constraint modeling, we suggest a rule-based approach to represent the formal semantic constraints, and describe a detail mechanism to apply the rule-based specified constraints to the BPS in a prototype implementation.     

A superscalar simulation employing poisson distributed stalls

This paper presents a statistical approach to estimating the performance of a superscalar processor. Traditional trace-driven simulators can take a large amount time to conduct a performance evaluation of a machine, especially as the number of instructions increases. The result of this type of simulation is typically tied to the particular trace that was run. Elements such as dependencies, delays, and stalls are all a direct result of the particular trace being run, and can differ from trace to trace. This paper describes a model designed to separate simulation results from a specific trace. Rather than running a trace-driven simulation, a statistical model is employed, more specifically a Poisson distribution, to predict how these types of delay affects performance. Through the use of this statistical model, a performance evaluation can be conducted using a general code model, with specific stall rates, rather than a particular code trace. This model allows simulations to quickly run tens of millions of instructions and evaluate the performance of a particular micro-architecture while at the same time, allowing the flexibility to change the structure of the architecture.     

Learning criterion and inductive behaviour

Inductive behaviours may be classified according to their aim. We intend to show that there are at least two kinds of inductive behaviours. Most of the publications seem to take into consideration only one of these: to copy as exactly as possible the behaviour of a probability process. After a brief discussion to explain the necessity of a learning criterion and a recall about one criterion, representative of most of them, we shall define a new criterion, and show why it is better fitted to learn the laws of a deterministic process from a set of observations.This criterion has been used to implement a program which builds an acceptor of natural language sentences in a CAI environment using a tutorial strategy, and then for a question answering device. As attractive as the results are, their improvement requires a semantic model. We give the basic principles of a model which we currently develop, and whose main feature is approximation.     

Modern modeling of a classic multiperiod problem

In this paper we discuss the integration of modeling and programming in order to solve problems in operations research and decision support. Our goal is to integrate modeling into the larger programming scheme of things and, conversely, to inject programming into modeling. This integration leads to a technologically open way to handle problems in OR, AI, etc. since the full programming arsenal can be brought to bear on these problems and since both problem solving and model management can be abetted by software engineering techniques. Here, by means of variations on a single example, we will illustrate the solution of a linear program, a goal program, a disjunctive program, a hill climbing search, a branch and bound search, and a parallel solution to a stochastic problem.     

Realization of task intelligence for service robots in an unstructured environment

In order to perform various tasks using a robot in a real environment, it is necessary to learn the tasks based on recognition, to be able to derive a task sequence suitable for the situation, and to be able to generate a behavior adaptively. To deal with this issue, this paper proposes a system for realizing task intelligence having a memory module motivated by human episodic memory, and a task planning module to resolve the current situation. In addition, this paper proposes a technique that can modify demonstrated trajectories according to current robot states and recognized target positions in order to perform the determined task sequence, as well as a technique that can generate the modified trajectory without collisions with surrounding obstacles. The effectiveness and applicability of the task intelligence are demonstrated through experiments with Mybot, a humanoid robot developed in the Robot Intelligence Technology Laboratory at KAIST.     

A self-adaptation scheme for workflow management in multi-agent systems

Business processes, operational environment, variability of resources and user needs may change from time to time. An effective workflow management software system must be able to accommodate these changes. The ability to dynamically adapt to changes is a key success factor for workflow management systems. Holonic multi-agent systems (HMS) provide a flexible and reconfigurable architecture to accommodate changes based on dynamic organization and collaboration of autonomous agents. Although HMS provides a potential architecture to accommodate changes, the dynamic organization formed in HMS poses a challenge in the development of a new software development methodology to dynamically compose the services and adapt to changes as needed. This motivates us to study and propose a methodology to design self-adaptive software systems based on the HMS architecture. In this paper, we formulate a workflow adaptation problem (WAP) and propose an interaction mechanism based on contract net protocol (CNP) to find a solution to WAP to compose the services based on HMS. The interaction mechanism relies on a service publication and discovery scheme to find a set of task agents and a set of actor agents to compose the required services in HMS. We propose a viable self-adaptation scheme to reconfigure the agents and the composed services based on cooperation of agents in HMS to accommodate the changes in workflow and capabilities of actors. We propose architecture for our design methodology and present an application scenario to illustrate our idea.     

A new deterministic approach in a decision support system for ship’s trajectory planning

The paper introduces a Decision Support System for ships, developed to solve a problem of collision avoidance with static and dynamic obstacles. The system maps the decision making capability of a human (navigation) expert to solve the path planning problem for a ship in a complex navigation environment. It can be further developed to provide automatic control of a ship. It utilizes a new, fast and effective, deterministic method, called the Trajectory Base Algorithm, to calculate a safe, optimal path for a ship. The system structure, a detailed explanation of a new method, followed by results of simulation tests are all presented in the paper. The results proof a successful application of the method to solve a path planning problem for ships with the consideration of both static and dynamic obstacles in the environment, marine traffic regulations and dynamic properties of a ship, what makes this approach applicable in commercial systems. The approach can also be adapted for application in mobile robots path planning. The experimental results and ability of the system to achieve a new functionality of full autonomy show significance of this contribution to the development of Expert and Intelligent Systems domain. The author believes that autonomous systems constitute the future of Expert and Intelligent Systems.     

Analysis of landmarks in recognition of face expressions

Facial expression is a powerful mechanism used by humans to communicate their emotions, intentions, and opinions to each other. The recognition of facial expressions is extremely important for a responsive and socially interactive human-computer interface. Such an interface with a robust capability to recognize human facial expressions should enable an automated system to effectively deploy in a variety of applications, including human computer interaction, security, law enforcement, psychiatry, and education. In this paper, we examine several core problems in face expression analysis from the perspective of landmarks and distances between them using a statistical approach. We have used statistical analysis to determine the landmarks and features that are best suited to recognize the expressions in a face. We have used a standard database to examine the effectiveness of landmark based approach to classify an expression (a) when a face with a neutral expression is available, and (b) when there is no a priori information about the face.     

TreeNetViz: revealing patterns of networks over tree structures

Network data often contain important attributes from various dimensions such as social affiliations and areas of expertise in a social network. If such attributes exhibit a tree structure, visualizing a compound graph consisting of tree and network structures becomes complicated. How to visually reveal patterns of a network over a tree has not been fully studied. In this paper, we propose a compound graph model, TreeNet, to support visualization and analysis of a network at multiple levels of aggregation over a tree. We also present a visualization design, TreeNetViz, to offer the multiscale and cross-scale exploration and interaction of a TreeNet graph. TreeNetViz uses a Radial, Space-Filling (RSF) visualization to represent the tree structure, a circle layout with novel optimization to show aggregated networks derived from TreeNet, and an edge bundling technique to reduce visual complexity. Our circular layout algorithm reduces both total edge-crossings and edge length and also considers hierarchical structure constraints and edge weight in a TreeNet graph. These experiments illustrate that the algorithm can reduce visual cluttering in TreeNet graphs. Our case study also shows that TreeNetViz has the potential to support the analysis of a compound graph by revealing multiscale and cross-scale network patterns.     

A distributed learning model for Freshwater Ecology practical classes

Abstract This paper describes a case study where a distributed learning model was used to enhance the traditional teaching of a freshwater ecology practical class by providing students with a student-centred constructivist environment. Prior to the practical session, a website was created and students were encouraged to think about the morphological adaptations of stream organisms. They were then divided into groups and taken to a real stream to collect specimens and bring them back to the laboratory for further examination and discussion. After the practical, each student group was required to produce a web page concerning the adaptations of the stream organisms to answer a set of online tutorial questions, and to participate in web-based discussion. Feedback by questionnaire showed that the great majority of students enjoyed working with the website and found the content very useful. More than half of the students preferred this type of web-assisted, student-centred practical to conventional practicals, while about a third showed no special preference between the two approaches.     

Wearable vibrotactile systems for virtual contact and information display

This paper presents a development history of a wearable, scalable vibrotactile stimulus delivery system. This history has followed a path from desktop-based, fully wired systems, through hybrid approaches consisting of a wireless connection from the host computer to a body-worn control box and wires to each tactor, to a completely wireless system employing Bluetooth technology to connect directly from the host to each individual tactor unit. Applications for such a system include delivering vibrotactile contact cues to users of virtual environments, providing directional cues in order to increase situational awareness in both real and virtual environments, and for general information display in wearable contexts. Through empirical study, we show that even a simple configuration, such as eight tactors arrayed around the torso, can be effective in increasing situational awareness in a building-clearing task, compared to users who perform the same task without the added cues.