Chung-Han Chen

Unequal Error Protection (UEP) for Wavelet-Based Wireless 3D Mesh Transmission

The recent popularity of networked graphicsapplications such as distributed military simulators andonline games, has increased the need to transmit large 3Dmeshes and textures over wireless networks. To speed up large mesh transmission over low-bandwidth wireless links, we use a wavelet-based technique that aggressively compresses large meshes and enables progressive (piece-wise) transmission. Using wavelets, a server only needs to send the full connectivity information of a small base mesh along with wavelet coefficients that refine it, saving memory and bandwidth. To mitigate packet losses caused by high wireless error rates, we propose a novel Forward Error Correction (FEC) scheme based on Unequal Error Protection (UEP). UEP adds more error correction bits to regions of the mesh that have more details. Our work uses UEP to make wavelet-encoded meshes more resilient to wireless errors. Experimental results shows that our proposed UEP scheme is more error-resilient than NoError Protection (NEP) and Equal Error Protection (EEP) asthe packet loss rate increases by achieving 50% less relative errors and maintaining the decoded mesh structure. Our scheme can be integrated into future mobile devices and shall be useful in application areas such as military simulators on mobile devices.

Imperceptible Simplification on Mobile Displays

Graphics on mobile devices is becoming popular because untethered computing is convenient and makes workers more productive. Mobile displays have a wide range of resolutions that affect the scene Level-of-Detail LoD that users can perceive: smaller displays show less detail, therefore lower resolution meshes and textures are acceptable. Mobile devices frequently have limited battery energy, low memory and disk space. To minimize wasting limited system resources, the authors render mobile graphics scenes at the lowest LoD at which users do not perceive distortion due to simplification. This is called LoD the Point of Imperceptibility PoI. Increasing the mesh or texture resolution beyond the PoI wastes valuable system resources without increasing perceivable visual realism. The authors propose a perceptual metric that can easily be evaluated to identify the LoD corresponding to a target mobile displays PoI and accounts for object geometry, lighting and shading. Previous work did not directly compute changes in the PoI due to target screen resolution. The perceptual metric generates a screen-dependent Pareto distribution with a knee point that corresponds to the PoI. We employ wavelets for simplification, which gives direct access to the mesh undulation frequency that we then use to parameterize the CSF curve.

An Efficient Acceleration of Symmetric Key Cryptography Using General Purpose Graphics Processing Unit

Graphics Processing Units (GPU) have been the extensive research topic in recent years and have been successfully applied to general purpose applications other than computer graphical area. The nVidia CUDA programming model provides a straightforward means of describing inherently parallel computations. In this paper, we present a study of the efficiency of emerging technology in applying General Purpose Graphics Processing Units (GPGPU) in high performance symmetric key cryptographic solutions. We implemented symmetric key cryptography algorithm using the novel CUDA platform on nVidia Geforce 280 GTX and compared its performance with an optimized CPU implementation on a high-end AMD Opteron Dual Core CPU. Our experimental results show that GPGPU can perform as an efficient cryptographic accelerator and the developed GPU based implementation achieve a significant performance improvement over CPU based implementation and the maximum observed speedups are about 100 times.

Sensitive Data Protection on Mobile Devices

Nowadays, many mobile devices such as phones and tablets are used in the workplace. A large amount of data is being transferred from one person to another. Data transfer is used for several different fields. Many companies and institutions are focusing on research and development on the way to further protect sensitive data. However, sensitive data still get leaks on mobile devices. To analyze how sensitive data get leak, a simulation on transferring sensitive data is developed. In this paper, we present the analysis of mobile security problem dealing with sensitive data from getting out. The goals in our research are for users to have a greater understanding on how data is being transferred and prevention sensitive data from being stolen. Our work will benefit mobile device users and help to prevent sensitive data from being stolen. Our experiments show different ways to safely transfer information on mobile devices by testing three methods types, which are back-up, encryption, and lock plus wipe data.

Introducing cryptography course in computer science undergraduate curricula

With the advent of the Internet and the World Wide Web, Information Assurance (IA) has become very important and crucial. To ensure the security of information in increasingly prevalent e-commerce, e-business, and to protect private data from hackers and saboteurs, professionals should have sound knowledge in the area of information assurance. Among the others, cryptography is one of the key techniques that ensure confidentiality and integrity of information. It is essential to establish a cryptography course, as part of the information assurance curricula to provide computer science majors such knowledge. Traditionally, courses in cryptography have been heavily mathematical in nature and are usually offered in the graduate level. This paper proposes the introduction of cryptography course in Computer Science at undergraduate level as part of our Information Assurance curricula. To make the proposed course suitable for the undergraduate majors, we skip some complicate mathematical theory and algorithms and include more cryptography protocols, techniques, and applications. This course will provide students majoring in computer science a broad background in Cryptography for Information Assurance, which has become an essential part of software development in the present day insecure world.

On Balancing Energy Consumption, Rendering Speed, and Image Quality on Mobile Devices

Mobile games and graphics are popular because un-tethered computing is convenient and ubiquitous entertainment is compelling. However, rendering graphics on mobile devices faces challenges due to limited system resources, such as battery energy, and low memory and disk space. Real time frame rates, low energy consumption and high image quality are all desirable attributes of interactive mobile graphics; however, achieving these objectives is conflicting. For instance, increasing mesh resolutions improves rendered image quality but consumes more battery energy. Therefore, the authors propose a mobile graphics heuristic to minimize energy consumption while maintaining acceptable image quality and interactive frame rates. Over the lifetime of a mobile graphics application, scene complexity, animation paths, user interactivity and other elements all change its CPU and resource demands. In this regard, a heuristic that dynamically changes scene mesh LoDs and amount of CPU timeslices allotted to the mobile graphics application is presented to select optimal operating conditions that balance rendering speed, energy conservation and image quality. Additionally, a workload predict model is proposed so that the heuristic can monitor both application workload and the availability of resources of mobile devices periodically, while adaptively determining how much resources will be allocated to applications.

Infusing Information Assurance into an Undergraduate CS Curriculum

With the advent of the Internet and the World Wide Web, the focus on securing information has become a topic of increasing importance. To ensure the security of information in a society of e-commerce, e-business, and e-sharing it is essential for graduates of computer science departments to be trained in the fundamentals of information security and to gain hands-on experience with security tools. To address this issue computer science educators are turning their attentions to the development of software and information security courses. The goal of this paper is to describe the development of an Information Assurance track in Computer Science and Information Systems at the undergraduate level. The paper describes existing courses that have been modified to include security concepts as well as the paper introduces the new courses that have been developed.