• International Journal of Naval Architecture and Ocean Engineering
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• 제7권3호
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• pp.526-539
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• 2015

Stirling engines are regarded as an efficient and promising power system for underwater devices. Currently, many researches on one-dimensional model is used to evaluate thermodynamic performance of Stirling engine, but in which there are still some aspects which cannot be modeled with proper mathematical models such as mechanical loss or auxiliary power. In this paper, a four-cylinder double-acting Stirling engine for Unmanned Underwater Vehicles (UUVs) is discussed. And a one-dimensional model incorporated with empirical equations of mechanical loss and auxiliary power obtained from experiments is derived while referring to the Stirling engine computer model of National Aeronautics and Space Administration (NASA). The P-40 Stirling engine with sufficient testing results from NASA is utilized to validate the accuracy of this one-dimensional model. It shows that the maximum error of output power of theoretical analysis results is less than 18% over testing results, and the maximum error of input power is no more than 9%. Finally, a Stirling engine for UUVs is designed with Schmidt analysis method and the modified one-dimensional model, and the results indicate this designed engine is capable of showing desired output power.

• 한국태양에너지학회 논문집
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• 제33권3호
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• pp.67-74
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• 2013

These days, although thermal energy is decreasing, electric energy is increasing in building. Also, it is very important to research and distribute BIPV(Building Integrated photovoltaic) because our society consider electricity more significant than other energy in building. Therefore, in this paper, our research team analyzed difference between BIPV yield and building energy consumption through experimental research. As a result, yearly building energy consumption was 104,602.4kWh and BIPV yield was 105,267kWh. And then, totally counterbalanced time took up 26%, reduced electric load time took up 16%. In other words, peak load could be reduced up to 42% by BIPV. As a result, yearly building energy consumption was 104,602.4kWh and BIPV yield was 105,267kWh. And then, totally counterbalanced time took up 26%, reduced electric load time took up 16%. In other words, peak load could be reduced up to 42% by BIPV.

• 한국정보처리학회:학술대회논문집
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• 한국정보처리학회 2004년도 춘계학술발표대회
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• pp.857-860
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• 2004

인터넷 사용인구가 전 국민의 3분의 2가 넘었고, 초고속 인터넷 설치가구가 벌써 1,100만 이상에 이르게 되었다. 점점 더 사람들은 디지털 생활에 익숙해져 가고 있고, 디지털을 떠나서 살아갈 수 없게 되고 있다. 이러한 분위기에 더하여 가정내의 가전기기들도 디지털화 되고 있고, 이것들을 네트워크로 연결하여 원격지에서 제어하는 홈 네트워크 관련 기술들이 현실화 되고 있다. 그러나, 여러 가전회사들이 각자의 미들웨어를 만들고 이것을 이용해서 제품들을 만들고 있다. 따라서 스마트 홈(Smart Home)[1]을 구성하기 위한 여러 가지 미들웨어 제안들이 나오게 되었고, 이것들은 계속 혼재할 것으로 예상되어 실제로 홈 네트워크를 구성하는데 많은 혼란이 예상되고 있다. 본 논문에서는 여러 가지 미들웨어를 통합하는 OSGi(Open Service Gateway Initiative)[2,3]를 기반으로 구성된 스마트 홈 시스템 아키텍처를 제안하여 홈 네트워크 구성에 대한 위험 부담이 적고 신뢰할 수 있는 방법을 제시하고자 한다.

• Architectural research
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• 제20권4호
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• pp.103-108
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• 2018

Wandering behavior is a serious problem among the elderly in nursing homes, yet it has received relatively little study As multi-family houses built before the '80s in South Korea were designed, it did not take account into issues related to parking so that at present parking became a big issue. The Seoul Metropolitan Government tried various ways to sort out the parking problem in multi-family house areas, but inadequate parking and illegal parking are still an ongoing problem. Thus, the purpose of this study was to examine current situation on resident parking only and illegal parking centered on a congested area of multi-family houses in Seoul and present the improvement plan of parking problems through case investigation home and abroad. As the result of the survey, it has been identified that the subject area consists of 506 households in total and 186 parking spaces and also, 100 cars in parking space or parking lot in housing space and 143 in illegal parking. Green parking business and open access parking system were suggested as solution plan for parking problem. Thus, it is expected that through green parking business for 6 houses and the parking lot of elementary schools around, the illegal parking problem would be sorted out.

• 대한건축학회논문집:계획계
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• 제35권1호
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• pp.19-28
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• 2019

The purpose of this study is to evaluate the walking behavior analysis methodology used in the previous studies, paying attention to the demand for empirical data collecting for urban and neighborhood planning. The preceding researches are divided into (1)Recording, (2) Surveys, (3)Statistical data, (4)Global positioning system (GPS) devices, and (5)Mobile Big Data analysis. Next, we analyze the precedent research and identify the changes of the walkability research. (1)being required empirical data on the actual walking and moving patterns of people, (2)beginning to be measured micro-walking behaviors such as actual route, walking facilities, detour, walking area. In addition, according to the trend of research, it is analyzed that the use of GPS device and the mobile big data are newly emerged. Finally, we analyze pedestrian data based on mobile big data in terms of 'application' and distinguishing it from existing survey methodology. We present the possibility of mobile big data. (1)Improvement of human, temporal and spatial constraints of data collection, (2)Improvement of inaccuracy of collected data, (3)Improvement of subjective intervention in data collection and preprocessing, (4)Expandability of walking environment research.

• 대한건축학회논문집:계획계
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• 제35권2호
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• pp.3-10
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• 2019

The purpose of the study is to survey the effective methodology of composition and connection for the third pedestrian routes in mixed-use building by case studies. The study is performed as follows: First of all, pedestrian routes are classified into malling route, evacuation route, and the Third route. Secondly, case studies are conducted based on the classification. Thirdly, it is investigated about the composition and connection of the malling and the Third pedestrian route. The investigation is focused on gate, path, central area, vertical circulation(EV and escalator) and the four circulation elements. Finally, the effective methodology is extracted for setting the Third route in mixed-use buildings. The conclusion of the study is as follows: The enhancement of consistency and connection between the main route and the Third route is important for providing convenient paths especially to users who needs shortcut, EV/ES users. Additionally, the connections between EV and gate, between shortcut and EV/ES should be increased to enable users choosing their path as needed.

• 대한건축학회논문집:계획계
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• 제35권12호
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• pp.75-82
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• 2019

After 1840 the first opium war, that changed the social nature and living habitats in China. The purpose of this study is to observe the influence of the war on the plan layout of traditional Chinese residential houses in Beijing Siheyuan. To find out the changes that were made after 1840, and reservation of the past, the space syntax model is used to analyze different social contexts and also compare the ancient and modern residential buildings. The result of the study indicate the following: Before the war, the ancient Siheyuan people's way of life strictly abide by the hierarchy system; External emphasis shows the host's status. However, in modern times, the social status became equal, efficient and harmonious relationship internally, while externally, it arranged the orientation and position of buildings to adapt to the natural environment. However, the boundaries between family members and visitors the emphasis on the courtyard and respect for private life remain unchanged.

• 대한건축학회논문집:계획계
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• 제35권12호
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• pp.105-114
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• 2019

The goal of this study is to quantitatively evaluate the effects of the additional construction of urban railroads. To this end, 1) establish accessibility as a measure of quantitative evaluation of construction effects; 2) select the 'Integration' of Space Syntax as a quantifiable indicator of accessibility; 3) represent the Seoul railroads as a network; 4) calculate the 'Integration' form the network before and after the additional construction of the urban railroads. By calculating the change of the 'Integration' of the individual nodes and the change of the sum of the 'Integration' of given zones, the change in accessibility of a particular node and the change in accessibility of a particular region were calculated. After analyzing the change in accessibility in nodes and areas as well, it was confirmed that the additional construction of urban railroads was improving accessibility as a whole of Seoul. It was also identified that there was a degree of difference in the extent of the accessibility change for the different areas. It is particularly noteworthy that changes occur in the accessibility ranking. While certain regions were improving relative rankings, others fell in rank. With this finding, it could be argued that active consideration of the areas in which the relative decline occurs is needed when the planned urban railroad is being built.

• 정보보호학회논문지
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• 제12권2호
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• pp.53-64
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• 2002

This paper describes a design of cryptographic processor that implements the AES (Advanced Encryption Standard) block cipher algorithm, "Rijndael". An iterative looping architecture using a single round block is adopted to minimize the hardware required. To achieve high throughput rate, a sub-pipeline stage is added by dividing the round function into two blocks, resulting that the second half of current round function and the first half of next round function are being simultaneously operated. The round block is implemented using 32-bit data path, so each sub-pipeline stage is executed for four clock cycles. The S-box, which is the dominant element of the round block in terms of required hardware resources, is designed using arithmetic circuit computing multiplicative inverse in GF($2^8$) rather than look-up table method, so that encryption and decryption can share the S-boxes. The round keys are generated by on-the-fly key scheduler. The crypto-processor designed in Verilog-HDL and synthesized using 0.25-$\mu\textrm{m}$ CMOS cell library consists of about 23,000 gates. Simulation results show that the critical path delay is about 8-ns and it can operate up to 120-MHz clock Sequency at 2.5-V supply. The designed core was verified using Xilinx FPGA board and test system.

• 인터넷정보학회논문지
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• 제23권5호
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• pp.17-23
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• 2022

Network slicing is a promising paradigm and significant evolution for adjusting the heterogeneous services based on different requirements by placing dynamic virtual network functions (VNF) forwarding graph (VNFFG) and orchestrating service function chaining (SFC) based on criticalities of Quality of Service (QoS) classes. In system architecture, software-defined networks (SDN), network functions virtualization (NFV), and edge computing are used to provide resourceful data view, configurable virtual resources, and control interfaces for developing the modified deep reinforcement learning agent (MDRL-A). In this paper, task requests, tolerable delays, and required resources are differentiated for input state observations to identify the non-critical/critical classes, since each user equipment can execute different QoS application services. We design intelligent slicing for handing the cross-domain resource with MDRL-A in solving network problems and eliminating resource usage. The agent interacts with controllers and orchestrators to manage the flow rule installation and physical resource allocation in NFV infrastructure (NFVI) with the proposed formulation of completion time and criticality criteria. Simulation is conducted in SDN/NFV environment and capturing the QoS performances between conventional and MDRL-A approaches.