• Journal of the Korea Institute of Building Construction
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• v.16 no.6
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• pp.595-601
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• 2016

The insulation performance of the insulation currently used in building structures is reflected only during design based on initial performance and the reduction in heat insulation performance due to the degradation of long-term durability is not reflected. This study reviewed the degradation of heat insulation performance due to the durability degradation of insulating materials through the accelerated durability test. The study findings showed that the foamed polystyrene insulation bead method did not show performance degradation due to aging in the standard environmental condition and laboratory accelerated test condition but the performance is degraded in the freeze-thaw test condition. On the other hand, in the case of the extrusion method, the degradation of the heat insulation performance was less in the freeze-thaw test condition, but the rapid performance degradation was caused by the release of the internal gas at the beginning of aging. In addition, the hard polyurethane foam insulation showed better initial insulation performance than other insulation materials, but the performance was found to be degraded somewhat under laboratory accelerated test conditions and freeze-thaw test conditions.

• Journal of the Earthquake Engineering Society of Korea
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• v.24 no.3
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• pp.123-128
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• 2020

Analysis of the 2016 Gyeongju earthquake and the 2017 Pohang earthquake showed the characteristics of a typical high-frequency earthquake with many high-frequency components, short time strong motion duration, and large peak ground acceleration relative to the magnitude of the earthquake. Domestic nuclear power plants were designed and evaluated based on NRC's Regulatory Guide 1.60 design response spectrum, which had a great deal of energy in the low-frequency range. Therefore, nuclear power plants should carry out seismic verification and seismic performance evaluation of systems, structures, and components by reflecting the domestic characteristics of earthquakes. In this study, high-frequency amplification factors that can be used for seismic verification and seismic performance evaluation of nuclear power plant systems, structures, and equipment were analyzed. In order to analyze the high-frequency amplification factor, five sets of seismic time history were generated, which were matched with the uniform hazard response spectrum to reflect the characteristics of domestic earthquake motion. The nuclear power plant was subjected to seismic analysis for the construction of the Korean standard nuclear power plant, OPR1000, which is a reactor building, an auxiliary building assembly, a component cooling water heat exchanger building, and an essential service water building. Based on the results of the seismic analysis, a high-frequency amplification factor was derived upon the calculation of the floor response spectrum of the important locations of nuclear power plants. The high-frequency amplification factor can be effectively used for the seismic verification and seismic performance evaluation of electric equipment which are sensitive to high-frequency earthquakes.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.46 no.12
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• pp.87-95
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• 2009

In this paper, an area-efficient FFT processor is proposed for MIMO-OFDM based SDR systems. The proposed scalable FFT processor can support the variable length of 64, 128, 512, 1024 and 2048. By reducing the required number of non-trivial multipliers with mixed-radix (MR) and multi-path delay commutator (MDC) architecture, the complexity of the proposed FFT processor is dramatically decreased without sacrificing system throughput The proposed FFT processor was designed in hardware description language (HDL) and synthesized to gate4eve1 circuits using 0.18um CMOS standard cell library. With the proposed architecture, the gate count for the processor is 46K and the size of memory is 64Kbits, which are reduced by 59% and 39%, respectively, compared with those of the 4-channel radix-2 single-path delay feedback (R2SDF) FFT processor. Also, compared with 4-channel radix-2 MDC (R2MDC) FFT processor, it is confirmed that the gate count and memory size are reduced by 16.4% and 26.8, respectively.

• Journal of the Korea Furniture Society
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• v.24 no.4
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• pp.433-443
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• 2013

The furniture industry of the northern region of Gyeonggi Province consists of several regional complexes which was just autogenously, that is, not based on the organized and planned movements cultivated and clustered, so it stays small businesses. This fact certainly requires to find right courses for future policy direction, in order to develop the furniture industry centering in the northern region of Gyeonggi Province internationally competitive. Consequently the aim of the present study was to investigate the characteristics of the furniture industry in the northern region of Gyeonggi Province first and to present right development directions for the innovation of the structure of furniture industry according to the change of the times, i.e. to connect the industry, university and the authorities concerned well and to strengthen the technology level of furniture industry accordingly. In addition, this requires education and training of the excellent designers being able to create high added-value industrial sectors, including finding a new Korean national brand which should preoccupy the global market. Furthermore, the high-tech furniture industrial complex specialized in manufacture, distribution and marketing such as the division of work between business to business should be built and finally a Korean traditional & unique furniture culture should be created on the basis of a cultural approach of furniture industry. It would be the timing for entire business sectors related to Korea's furniture industry to establish an international standard certification like ISO, in order to upgrade the quality of furniture steadily while keeping our own tradition, and this belongs to a meaningful attempt for the high-tech lifestyles and the improvement in the quality of life of customers.

• Journal of the Korea Convergence Society
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• v.9 no.10
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• pp.69-74
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• 2018

IP and SIP public broadcasting systems developed in Korea and abroad are developed in a Windows or Linux server environments and are installed in a server-rack structure, have high power consumption, and are difficult to remotely respond to system failures. In this paper, IoT platform is designed to connect IoT device and gateway to IoT service server by using internet service structure. We also designed a server based on embedded OS that can provide a variety of public safety management services according to the order of the server with built-in call processing and broadcasting function that can handle emergency calls and emergency broadcasts in public places using this structure. This server is interoperable with a variety of SIP-based call and broadcast devices that support the standard SIP and can be integrated with an in-house phone and on-premises system.

• Journal of the Korean Geotechnical Society
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• v.21 no.9
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• pp.65-75
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• 2005

Maximum shear modulus of soil is a principal parameter for the design of earth structures under static and dynamic loads. In this study, the statistical data of maximum shear moduli of silty sands in Songdo area in the west coast of Korea evaluated by various field and laboratory tests - standard penetration test (SPT), cone penetration test (CPT), self-boring pressuremeter test (SBPT), downhole test (DH), seismic cone penetration test (SCPT) and resonant column test (RC) were analyzed. Based on the measurement of shear moduli using DH which is known as maximum value at very small strain, the new empirical correlations between shear moduli and SPT or CPT values were proposed. Predictions of maximum shear moduli using the proposed correlations were compared with the data obtained from DH. The good agreement confirmed that the proposed correlations reasonably predicted the maximum shear moduli of silty sands in the area.

• Journal of the Korean housing association
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• v.19 no.3
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• pp.95-104
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• 2008

The purpose of this study is systematically to examine the changes that have taken place to the community spaces of apartment complexes in the national capital region of Korea. The methodology used in this study entails analyzing existing research and case studies carried out on this subject matter. Prior to these case studies, an existing study had been made of the chronological changes in policy, related laws and regulations in Korea since the 1960s. This case study presents the component ratio and systematized present situation of community spaces in twenty-two apartment complexes. An analysis of the researching process has revealed the following important factors related to the changes that have occurred in community spaces in apartment complexes. (1) Apartment complexes were originally developed in the 1960s to ease the housing shortage. Because the priority was to solve the housing shortage, community spaces were not widely considered or developed. (2) The standard of community spaces was established as mandatory by law in the 1970s, resulting in the emergence of various facilities that provided community spaces. (3) In the 1980s, various design competitions for apartment complexes were conducted as an attempt to improve residential environments. This process resulted in the development of new characteristic of subsidiary facilities. (4) During the period when housing problems were being addressed in the 1990s, the Community Service Center was added to the welfare facilities for residents. (5) Recently, during the 2000s, an improvement in residential environments has evolved due to the expansion of housing supply and economic growth. The quality of community spaces has therefore improved from the 1960s onward. This study revealed that policy and related laws regarding community space in Korea have been developing in a suitable direction and that the addition of various facilities to community spaces has improved the quality of living environments.

• Journal of IKEEE
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• v.24 no.3
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• pp.838-844
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• 2020

In this paper, we propose an efficient Viterbi processor using Joint Viterbi detection and decoding (JVDD) algorithm for a for bluetooth low energy (BLE) system. Since the convolutional coded Gaussian minimum-shift keying (GMSK) signal is specified in the BLE 5.0 standard, two Viterbi processors are needed for detection and decoding. However, the proposed JVDD scheme uses only one Viterbi processor by modifying the branch metric with inter-symbol interference information from GMSK modulation; therefore, the hardware complexity can be significantly reduced without performance degradation. Low-latency and low-complexity hardware architecture for the proposed JVDD algorithm was proposed, which makes Viterbi decoding completed within one clock cycle. Viterbi Processor RTL synthesis results on a GF55nm process show that the gate count is 12K and the memory unit and the initial latency is reduced by 33% compared to the modified state exchange (MSE).

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.23 no.5
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• pp.369-382
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• 2011

This study investigated the tsunami force acting on onshore structures using a numerical program, three-dimensional one-field model for immiscible multi-phase flows, which is based on Navier-Stokes solver. In this paper, the characteristics of tsunami of oil storage tank and house structures studied to the distance between the seawall and structure. In addition, the study compared and analyzed the tsunami forces determined by considering drag force only and considering both drag and inertia forces. These numerical results were compared with the design standard. As a results, the case of considering the both forces is more close to numerical result than that of considering the drag force only.

• Journal of Korea Technology Innovation Society
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• v.18 no.2
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• pp.338-357
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• 2015

The purpose of this study is to present an objective basis for the entry point of a knowledge-based economy, that is used by quantitative analysis to serve as 'The Result of Wage Structure Survey' and 'Sample Design for Survey Report on Labor Conditions by Employment Type' of the Ministry of Employment & Labor. Entry criteria for a knowledge-based society, through the definition of a Bell and Toffler, was defined by the number of information workers more than the number of physical workers, and the information workers were classified by knowledge workers. To redefine the definition of Porat's typology of information workers, Korea Standard Classification of Occupation is classified by the job of knowledge, service, industry and agriculture. The result of the analysis is appeared the entry point of a knowledge-based economy by workers structural changes and annual wage structure changes has identified empirically-year 1980 the United States more than 20 years later in 2000. In addition, the economic contribution of knowledge occupation was confirmed to be the biggest by measuring the economic contribution of occupation classification in the knowledge society.