• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.31 no.10C
• /
• pp.991-999
• /
• 2006

This paper shows that the support growth of an optimum (minimum mean square-error) scalar quantizer for a Laplacian density is logarithmic with the number of quantization points. Specifically, it is shown that, for a unit-variance Laplacian density, the ratio of the support-determining threshold of an optimum quantizer to $\frac 3{\sqrt{2}}1n\frac N 2$ converges to 1, as the number of quantization points grows. Also derived is a limiting upper bound that says that the optimum support cannot exceed the logarithmic growth by more than a constant. These results confirm the logarithmic growth of the optimum support that has previously been derived heuristically.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.7 no.12
• /
• pp.3071-3095
• /
• 2013

Configuring optimization of wireless sensor networks, which can improve the network performance such as utilization efficiency and network lifetime with minimal energy, has received considerable attention in recent years. In this paper, a cross layer optimal approach is proposed for multi-source linear network and grid network under Rayleigh block-fading channels, which not only achieves an optimal utility but also guarantees the end-to-end reliability. Specifically, in this paper, we first strictly present the optimization method for optimal nodal number $N^*$, nodal placement $d^*$ and nodal transmission structure $p^*$ under constraints of minimum total energy consumption and minimum unit data transmitting energy consumption. Then, based on the facts that nodal energy consumption is higher for those nodes near the sink and those nodes far from the sink may have remaining energy, a cross layer optimal design is proposed to achieve balanced network energy consumption. The design adopts lower reliability requirement and shorter transmission distance for nodes near the sink, and adopts higher reliability requirement and farther transmission distance for nodes far from the sink, the solvability conditions is given as well. In the end, both the theoretical analysis and experimental results for performance evaluation show that the optimal design indeed can improve the network lifetime by 20-50%, network utility by 20% and guarantee desire level of reliability.

• Proceedings of the Korean Society for Technology of Plasticity Conference
• /
• 2001.05a
• /
• pp.186-189
• /
• 2001

In keeping with the needs of the times for energy and labor saving and simplifying production processes, interests has been growing in warm forging. Moreover, it is interested in increasing the material usage and production amounts. To improve the productivity and material usage, it is studied the process design of warm forging for socket. Until now, socket is manufactured by hot forging in hammer. The percentage of material usage is under $60\%$ in hammer forging. On the other han4 the percentage can be increased over $90\%$ in warm forging. To change the process from hot forging to warm forging, process designs must be performed. In this time, by using the FEM package, DEFORM-3D, we could get the shape of 1st process and minimum sealing pressure. They are very essential design data to decrease the trial and error. Practically, the overlap defect could be detected and eliminated with design modification of rib height and fillet radius. Moreover, forging load and minimum sealing pressure was defined by the 3D FEM analysis.

• ETRI Journal
• /
• v.35 no.2
• /
• pp.270-280
• /
• 2013

A fast intra-prediction method is proposed for High Efficiency Video Coding (HEVC) using a fast intra-mode decision and fast coding unit (CU) size decision. HEVC supports very sophisticated intra modes and a recursive quadtree-based CU structure. To provide a high coding efficiency, the mode and CU size are selected in a rate-distortion optimized manner. This causes a high computational complexity in the encoder, and, for practical applications, the complexity should be significantly reduced. In this paper, among the many predefined modes, the intra-prediction mode is chosen without rate-distortion optimization processes, instead using the difference between the minimum and second minimum of the rate-distortion cost estimation based on the Hadamard transform. The experiment results show that the proposed method achieves a 49.04% reduction in the intra-prediction time and a 32.74% reduction in the total encoding time with a nearly similar coding performance to that of HEVC test model 2.1.

• Journal of the Korean Institute of Intelligent Systems
• /
• v.22 no.5
• /
• pp.663-668
• /
• 2012

A TPMS(Tire Pressure Monitoring System) is a wireless communication system designed to monitor the pressure and temperature of pneumatic tires of a vehicle. In order to provide the aid in protecting a driver, this system reports tire pressure information to the driver of the vehicle. Since the wireless communication technique should be employed to transmit the TPMS data from each tire to signal processing unit in the vehicle, it suffers from interference signals from external electrical or electronics equipments. In this paper, we propose the TPMS interference cancellation technique based on GSC(Generalized Sidelobe Canceler), which does not have only the excellent performance like MVDR(Minimum-Variance-Distortionless-Response) but also has the low computational complexity comparing with MVDR. The performance of interference suppression is conformed by computer simulation examples.

• International Journal of Oral Biology
• /
• v.38 no.2
• /
• pp.51-54
• /
• 2013

Methicillin-resistant Staphylococcus aureus (MRSA) is one of the important causative microbes for nosocomial infection and has been isolated from the dental environment. The purpose of this study was to investigate the antimicrobial activity of linalool and ${\alpha}$-terpineol against MRSA isolates from a Korean population. In the experiments, we determined the minimum inhibitory concentrations (MICs) and minimum bactericidal concentrations (MBCs) of these two compounds against 18 strains of MRSA. The data revealed that the $MIC_{90}/MBC_{90}$ values of linalool and ${\alpha}$-terpineol against MRSA were >12.8 mg/ml and 6.4 mg/ml, respectively. These results indicate that ${\alpha}$-terpineol has more potent antimicrobial activity against MRSA than linalool and may have utility as an anti-MRSA cleansing agent for dental instruments and dental unit chairs.

• Proceedings of the Korean Institute of Interior Design Conference
• /
• 2007.11a
• /
• pp.30-36
• /
• 2007

Recently, many performing arts facilities are under construction to accommodate people's various interest in cultural experiences. However, due to Korea's lack of know-how in such constructions and an absence of proper regulations on design planning, each designer designs and constructs the facilities differently, so several problems are occurring in the process of construction, such as high production cost for stage sets, high labor cost, low efficiency of stage work, and complicated work process. This resulted in low quality production of performance. This study is conducted to address the need for a systematic study on stage floor, and to propose an efficient way of regulating stage work in existing performing arts facilitiesand new facilities to be built. By a comparative analysis of performing arts facilities in Korea, and by analyzing stage floors of the facilities, this research suggests minimum modules as well as an appropriate unit of modules based on the minimum modules; and provides basic data on stage floors, which can be used for remodeling existing facilities orfor planning new cultural facilities. Also, this study suggests various ways of utilizing performing arts facilities in Korea.

• Economic and Environmental Geology
• /
• v.37 no.6 s.169
• /
• pp.631-645
• /
• 2004

This study assesses groundwater vulnerability to contaminants in industrial and residential/commercial areas of the city of Changwon, using DRASTIC technique and groundwater data. The DRASTIC technique was originally applied to situations in which the contamination sources are at the ground surface, and the contaminants flow into the groundwater with infiltration of rainfall. Mostly the industrial area has higher DRASTIC indices than the residential/commercial area. However, a part of the residential/commercial area having much groundwater production and great drawdown is more contaminated in groundwater than other industrial and the residential/commercial areas even if it has lowest DRASTIC indices in the study area. It indicates that groundwater contamination in urban areas can be closely related to excessive pumping resulting in a lowering of the water level. The correlation coefficient between minimum DRASTIC indices and the degree of poor water quality for 10 districts is as low as 0.40. On the other hand, the correlation coefficients between minimum DRASTIC indices and the groundwater discharge rate, and between minimum DRASTIC indices and well distribution density per unit area are 0.70 and 0.87, respectively. Thus, to evaluate the potential of groundwater contamination in urban areas, it is necessary to consider other human-made factors such as groundwater withdrawal rate and well distribution density per unit area as well as the existing seven DRASTIC factors.

• Journal of the Institute of Electronics Engineers of Korea CI
• /
• v.48 no.5
• /
• pp.88-98
• /
• 2011

Recently, according as the importance of GIS(geography information system) database security is embossed, much researches had been achieved about GIS network security. But most such researches are weak against sourceful illegal reproductions and distributions of GIS vector data map. In this paper, we proposed an efficient layer unit contents based partial encryption technique in the vector map compression domain to prevent illegal distributions and unauthorized accesses. This method achieves a partial encryption about each central coordinate and directional parameters of a MCA(minimum coding attribute) that is created at the vector map compression processing in the vector space. First, the position encryption is applied as permutating randomly the center coordinate of each record that is minimum unit of vector map shape. And second, the direction encryption that changing shapes of vector map topography is applied as encrypting the direction of vertices's coordinates of each record. In experimental results, we confirmed that our proposed method can encipher the large volumed vector map data effectively in low computational complexity. Also, we could minimize the decline of compression efficiency that occurred by conventional contents based encryption schemes using AES or DES algorithms.

• Journal of Industrial Convergence
• /
• v.20 no.11
• /
• pp.19-25
• /
• 2022

In the development of existing games, it is judged that virtual world production was done by arranging game elements one by one. What is noteworthy here is the question of whether quality virtual worlds were efficiently produced in preparation for investment. In this study, we propose a methodology that can build an efficient virtual world based on the concept of modularization in an unreal engine. First, precedents were analyzed and five reference elements for modularization were extracted. In addition, the concept of an instance production pipeline was proposed by dividing it into four stages, and the minimum-unit instance modules for urban virtual world production were compressed into four. Finally, an urban virtual world constructed based on the minimum unit module and reference elements was implemented and presented. In conclusion, research on the production method centered on this efficiency is thought to be able to focus the time that designers or artists had to spend on production only on ideas and creativity. The limitations of the research are that the basic minimum module is limited to the city, and the derived reference elements and production pipelines have not been verified when implementing them with an unreal engine. Therefore, it is expected that various virtual world creation plans will be derived through more advanced modular research.