• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.17 no.2 s.105
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• pp.198-206
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• 2006

The GFSK Transceiver of 400 MHz ISM band for data communication is designed and fabricated. To reduce the occupied bandwidth of transmitted signal, the GFSK modulation is selected. The measured results of fabricated transceiver show the data rate of 2,400 bps at 8.5 kHz bandwidth, frequency deviation of less than ${\pm}3\;kHz$, sensitivity of -107 dBm at SINAD of 20 dB, BER of less than $1.8{\times}10^{-3}$ at -110 dBm input power. The fabricated transceiver is satisfied with the regulation of radio wave and has the good performance.

• Journal of Electrical Engineering and Technology
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• v.6 no.4
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• pp.573-579
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• 2011

To meet the scalability and performance requirements of data analyses, which often involve voluminous data, efficient parallel or concurrent algorithms and frameworks are essential. We present a high-performance Korean morphological analyzer which employs the MapReduce framework on the graphics processing unit (GPU). MapReduce is a programming framework introduced by Google to aid the development of web search applications on a large number of central processing units (CPUs). GPUs are designed as a special-purpose co-processor. Their programming interfaces are typically formulated for graphics applications. Compared to CPUs, GPUs have greater computation power and memory bandwidth; however, GPUs are more difficult to program because of the design of their architectures. The performance of the Korean morphological analyzer using the MapReduce framework on the GPU is evaluated in comparison with the CPU-based model. The proposed Korean Morphological analyzer shows promising scalable performance on distributed computing with the GPU.

• Journal of Korea Multimedia Society
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• v.7 no.12
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• pp.1754-1764
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• 2004

Lately mobile handheld devices such as Personal Digital Assistant (PDA) and cellular phones are getting more popular for personal web surfing. However, today most mobile handheld devices have relatively poor web browsing capability due to their low performance so their users have to suffer longer communication latency than those of desktop Personal Computers (PCs). In this paper, we propose an effective pre-refresh mechanism for embedded web browser of mobile handheld devices to reduce this problem. The proposed mechanism uses the idle time to pre-refresh the expired web objects in an embedded web browser's cache memory. It increases the utilization of Central Processing Unit (CPU) power and network bandwidth during the idle time and consequently reduces the client's latency and web browsing cost. An experiment was done using a simulator designed by us to evaluate the efficacy of the proposed mechanism. The experiment result demonstrates that it has a good performance to make web surfing faster.

• Journal of information and communication convergence engineering
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• v.8 no.3
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• pp.245-250
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• 2010

To support various bandwidth requirements for many kinds of devices such as PC, notebook, PDA, cellular phone, a transcoding proxy is usually necessary to provide not only adapting multimedia streams to the client by transcoding, but also caching them for later use. Due to huge size of streaming media, we proposed the 3 kinds of segmentation - PT-2, uniform, bitrate-based segmentation. And to reduce the CPU cost of transcoding video, we proposed the DQS service policy. In this paper, we simulate the combined our previous two researches that are bitrate-based segmentation and DQS(Degraded Quality Service) policy. Experimental results show that the combined policy outperforms companion schemes in terms of the byte-hit ratios and delay saving ratios.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.3
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• pp.1071-1090
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• 2016

Most of scheduling methods in the Grid only consider one special attribute of the resource or one aspect of QoS (Quality of Service) of the job. In this paper, we focus on the problem that how to consider two aspects simultaneously. Based on the requirements of the jobs and the attributes of the resources, jobs are categorized into three kinds: CPU-overload, memory-overload, and bandwidth-overload jobs. One job may belong to different kinds according to different attributes. We schedule the jobs in different categories in different orders, and then propose a scheduling method-MTS (multiple attributes scheduling method) to schedule Grid resources. Based on the comparisons between our method, Min-min, ASJS (Adaptive Scoring Job Scheduling), and MRS (Multi-dimensional Scheduling) show: (1) MTS reduces the execution time more than 15% to other methods, (2) MTS improves the number of the finished jobs before the deadlines of the jobs, and (3) MTS enhances the file size of transmitted files (input files and output files) and improves the number of the instructions of the finished jobs.

• Proceedings of the Korean Information Science Society Conference
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• 2002.10e
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• pp.151-153
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• 2002

Mobile handhold devices such as PDA(Personal Digital Assistant) and Cellular Phone are more and more popular for personal web surfing. But today, most mobile handheld devices have relatively poor web browsing capability because of the small bandwidth of wireless connection, the small speed of CPU, the small capacity of RAM and Flash ROM, the small display size of LCD and the short lifecycle of battery. Users have to endure bigger communication latency than Desk PC's one because of these factors. In this paper, we propose an effective pre-refresh mechanism for handheld device's embedded web browser so as to make user's web surfing faster. The experiment was done using the simulator designed by ourselves and the experiment result demonstrates the proposed mechanism has a good performance to make web surfing faster.

• IEIE Transactions on Smart Processing and Computing
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• v.4 no.2
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• pp.78-82
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• 2015

General-purpose graphics processing units (GPGPUs) provide tremendous computational and processing power. Despite the latency hiding mechanism, a GPU architecture requires high memory bandwidth and lower latency between computational units and the memory system. For this reason, the current GPU architecture has private L1 caches in each core and a shared L2 cache to increase performance by reducing memory latency. But in some cases, this CPU-like cache design is not suitable for GPGPUs. In this paper, we analyze detailed cache performance related to GPGPU application characteristics, and suggest technical alternatives for the GPGPU architecture as future work.

• The Journal of the Korea Contents Association
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• v.9 no.9
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• pp.41-50
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• 2009

A conventional middleware system is optimized for wired computing environments. The wireless mobile devices have several disadvantages of low-speed processors, small memory and narrow bandwidth of wireless network. To overcome those problem issues in wireless mobile environments, middleware and many middleware-related applications have to be changed of the small sized components. In this paper, we design a lightweight mobile middleware system called "LightMware" which is optimized for mobile environment and middleware applications

• Electronics and Telecommunications Trends
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• v.37 no.1
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• pp.42-52
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• 2022

With the advent of the big data era, the memory capacity required for computing systems is rapidly increasing, especially in High Performance Computing systems. However, the number of DRAMs that can be used in a computing node is limited by the structural limitations of the hardware (for example, CPU specifications). Memory expansion technology has attracted attention as a means of overcoming this limitation. This technology expands the memory capacity by leveraging the external memory connected to the host system through hardware interface such as PCIe and CCIX. In this paper, we present an overview and describe the development trends of the memory expansion technology. We also provide detailed descriptions and use cases of the CCIX that provides higher bandwidth and lower latency than cases of the PCIe.

• Journal of KIISE:Information Networking
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• v.32 no.4
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• pp.471-482
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• 2005

The high-speed network permits Grid computing to handle large problem of management areas and share various computational resources. As there are many resources and changes of them in Grid computing, the resources should be detected effectively and matched correctly with tasks to provide high performance. In this paper, we propose a mechanism that maximizes the performance of Grid computing systems. According to a priority, grade and site of heterogeneous resources, we assign tasks to those resources. Initially, a volunteer's priority and ranking are determined by static information like as CPU speed, RAM size, storage size and network bandwidth. And then, the rank of resources is decided by considering dynamic information such as correctness, response time, and error rate. We find that overall Grid system performance is improved and high correctness using resource reallocation mechanism is achieved.