• Journal of the Institute of Convergence Signal Processing
• /
• v.3 no.3
• /
• pp.14-20
• /
• 2002

In this paper, we proposed the compression technique of the video data using SPIHT(set partitioning in hierarchical trees) based on wavelet and the multi-stream delivery method for best-effort service as fully utilizing the clients bandwidth over the current Internet. The experiment shows that the proposed method provides about 1.5dB better picture quality without block effects than DCT(discrete consine transform) based coding schemes at the same bit rates because of using the wavelet video coder. In addition, this technique implements the multi-stream transmission based on TCP(transmission control protocol). Thus, it is provided with the best-efforts service which is robust to the network jitter problem, and maximally utilizes the bandwidth of the client's.

• Journal of KIISE:Computing Practices and Letters
• /
• v.16 no.6
• /
• pp.722-726
• /
• 2010

The recent deployment of RIA (Rich Internet Application) is often involved with the complex JavaScript code, which leads to the announcement of high performance JavaScript engines for its efficient execution. And the Sunspider benchmark is being widely used for the performance evaluation of these JavaScript engines. In this paper, we compare the execution methods of three high-performance JavaScript engines, Mozilla TraceMonkey, Google V8, and Apple SquirrelFish Extreme, and measure their performances using the SunSpider benchmark. We also evaluate the pros and cons of each engine, based on its execution method and the code characteristics of the SunSpider benchmarks.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.26 no.1
• /
• pp.45-54
• /
• 2002

The breakup phenomena of a vertical laminar jet issuing from capillary tubes in a quiescent ambient air are investigated using a forced vibration analysis of the surface wave. Using a linear approach to the transient jet velocity, an approximate solution fur the longitudinal motion of a vertical liquid jet is theoretically derived, thus performing an instability analysis by a vibration method. The damping term of this equation is nonlinear as it depends on dimensionless parameters, a Weber number, and an Ohnesorge number. The instability condition is determined based on whether the coefficient of the damping term is less than zero or not. Uniform drop formation is dependent on the vibration frequency fur the forced vibration case.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.29 no.12
• /
• pp.645-653
• /
• 2017

Thermal and flow modeling and fin structure optimization were performed to reduce the weight of an electrical device with a staggered fin. First, a numerical model for thermal and flow characteristics was suggested, and then, the model was verified experimentally. Using the verified model, improvement in cooling performance of the cooling system through the staggered fins was predicted. As a result, 87.5% of total heat generated was dissipated through the cooling fins, and a thermal island was observed in the rotor because of low velocity of the internal air flow through the air gap. In addition, it was confirmed that the staggered fin improves the cooling performance but it also increases the total pressure drop within the cooling system, by maximizing the leading edge effect. Based on this analysis result, the effect of each design parameter on the thermal and flow characteristics was analyzed to select the main optimal design parameters, and multi-objective optimization was performed by considering the cooling performance and the fin weight. In conclusion, the optimized fin structure improved the cooling performance by 7% and reduced the fin weight by 28% without any compromise of the pressure drop.

• Journal of Korean Society of Archives and Records Management
• /
• v.5 no.2
• /
• pp.103-124
• /
• 2005

The purpose of the study is to propose the necessity of management and long-term preservation of dataset as records. Although government and corporate bodies produce various dataset in the regular course of the business, dataset have been stored and managed in the information system. Dataset as records should be captured into the record management system and managed in the overall system. They can provide a evidence of the decision-making process of the government and fundamental information of the process. If agents do not perform the right management, dataset records will disappear in the future.

• Journal of the Korean institute of surface engineering
• /
• v.53 no.5
• /
• pp.257-264
• /
• 2020

Anodization of Fe and Fe alloys is one of the most promising techniques to obtain iron oxide films applying to the various electrochemical devices due to their electrochemical catalytic properties. In this study, we investigate on the preparation of anodic iron oxide composite incorporated with WO₃ through a single-step anodization of stainless steel type-304 (STS304) as a substrate. The effects of applied voltage and tungsten precursor on the structural characteristics of iron oxide composite with different amount of incorporated WO₃ were observed. It is demonstrated that when the voltage of 60 V applied with 20 mM of Na₂WO₄ as a precursor, anodic iron oxide composite with a large pore diameter and a thick oxide length in which WO₃ is uniformly incorporated is obtained.

• Proceedings of the Korea Institute of Convergence Signal Processing
• /
• 2000.12a
• /
• pp.125-128
• /
• 2000

The conventional fractal decoding was required a vast amount computational complexity. Since every range blocks was implemented to IFS(iterated function system). In order to improve this, it has been suggested to that each range block was classified to iterated and non-iterated regions. If IFS region is contractive, then it can be performed a fast decoding. In this paper, a searched region of the domain in the encoding is limited to the range region that is similar with the domain block, and IFS region is a minimum. So, it can be performed a fast decoding by reducing the computational complexity for IFS in fractal image decoding.

• Journal of the Institute of Convergence Signal Processing
• /
• v.5 no.2
• /
• pp.85-90
• /
• 2004

This paper proposes the wavelet image coding using the significant cluster extraction by morphology and the adaptive quantization. In the conventional MRWD method, the additional seed data takes large potion of the total data bits. The proposed method extracts the significant cluster using morphology to improve the coding efficiency. In addition, the adaptive quantization is proposed to reduce the number of redundant comparative operations which are indispensably occurred in the MRWD quantization. The experimental result shows that the proposed algorithm has the improved coding efficiency and computational cost while preserving superior PSNR

• The Journal of the Convergence on Culture Technology
• /
• v.5 no.4
• /
• pp.361-366
• /
• 2019

Exchanging sheets for patients is one of the worst and one of the factors that makes the nursing environment difficult. Many beds with various functions for the patient have already been developed, but there is no device for automatically changing the sheets. In this study, we developed and tested the first automatic sheet changer for a medical bed and verified its performance. The developed automatic seat changer uses a torque limiter to properly adjust tension and exchange a dirty sheet and a new seat at the same time. The designed automatic sheet changer was experimentally confirmed to be properly operated and installed in a integrated multi-functional bed with bed sores prevention and automatic patient transfer functions.

• The Korean Journal of Archival Studies
• /
• no.56
• /
• pp.183-212
• /
• 2018

The study aimed at exploring a direction of development of the conceptual model for organizing public digital records. First, it started with reviewing the possibility of item-oriented records and archival organization, then analyzed RIC-CM developed by ICA EGAD. Second, it investigated the hierarchies of the classes and descriptive information applied to public digital records, as well as showed the necessities of transition from paper-based model to digital-based one. Based on these, it studied to seek possibilities for organizing public digital records not by record groups but by items. Finally, this study proposed the direction of development of the next generation conceptual model for organizing public digital records.