• Proceedings of the SAREK Conference
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• 2009.06a
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• pp.608-613
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• 2009

According to the building regulation U-value limitation of window is $3.3W/m^2{\cdot}K$ in southern regions, while U-value limitation of wall is $0.35{\sim}0.58W/m^2{\cdot}K$. It means that the energy loss through windows is five times more than it through wall. Therefore, this study analyze how much it has affected building energy rating when the insulation performance of windows and walls is changed by building regulation. In conclusion, in order to obtain 2 rating thermal performance of windows is improved more than 10 percent of U-value limitation and it of wall is improved more than 20 percent. The thermal performance of windows is improved more than 20 percent of U-value limitation and it of wall is improved more than 30 percent to receive 1 rating.

• Journal of the Korean Solar Energy Society
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• v.29 no.5
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• pp.59-64
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• 2009

According to the building regulation U-value limitation of window is $3.3W/m^2{\cdot}K$ in southern regions, while U-value limitation of wall is $0.35{\sim}0.58W/m^2{\cdot}K$. It means that the energy loss through windows is five times more than it through wall. Therefore, this study analyze how much it has affected building energy rating when the insulation performance of windows and walls is changed by building regulation. In conclusion, in order to obtain 2 rating thermal performance of windows is improved more than 10 percent of U-value limitation and it of wall is improved more than 20 percent. The thermal performance of windows is improved more than 20 percent of U-value limitation and it of wall is improved more than 30 percent to receive 1 rating.

• International Journal of Air-Conditioning and Refrigeration
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• v.12 no.1
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• pp.21-29
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• 2004

This paper is to study the heat transfer performance of the copper-water heat pipe with screen wicks. Recently, the semiconductor capacity of an electronic unit becomes larger, but its size becomes much smaller. As a result, a high- performance cooling system is needed. Experimental variables are inclination angles, temperatures of cooling waters and the mesh number of screen wicks. The distilled water was used as a working fluid. Based on the experimental results, when the copper-water heat pipe of 6mm diameter is used at the top heat mode, the heat transfer performance of 100 mesh 2 layers heat pipe is better than that of 150 and 200 mesh. The thermal resistance of the two layers with the 100-mesh screen was 0.7-$0.8^{\circ}C$/W.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.14 no.12
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• pp.1023-1030
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• 2002

This paper is to research the heat transfer characteristic performance of the copper-water heat pipe with the screen wicks. Recently, the semiconductor capacity of an electronic unit has been larger, on the contrary, its size has been much smaller. As a result, a high-performance cooling system is needed. Experimental variables are inclination angles, temperatures of cooling water and the mesh number of screen wicks. The distilled water was used for the working fluid. At the inclination angle $6^{\circ}$ in top heat mode, the two layers of the 100-mesh screen wick showed the best heat transfer performance. The thermal resistance of the two layers with the 100-mesh screen was 0.7~$0.8^{\circ}C$/W.

• Journal of the Korean Operations Research and Management Science Society
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• v.36 no.1
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• pp.39-55
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• 2011

Process monitoring has been emphasized for the monitoring of complex system such as chemical processing industries to achieve the efficiency enhancement, quality management, safety improvement. Recently, ICA (Independent Component Analysis) based MSPC (Multivariate Statistical Process Control) was widely used in process monitoring approaches. Moreover, DICA (Dynamic ICA) has been introduced to consider the system dynamics. However, the existing approaches show the limitation that their performances are strongly dependent on the statistical distributions of control variables. To improve the limitation, we propose a novel approach for process monitoring by integrating DICA and LOF (Local Outlier Factor). In this paper, we aim to improve the fault detection rate with the proposed method. LOF detects local outliers by using density of surrounding space so that its performance is regardless of data distribution. Therefore, the proposed method not only can consider the system dynamics but can also assure robust performance regardless of the statistical distributions of control variables. Comparison experiments were conducted on the widely used benchmark dataset, Tennessee Eastman process (TE process), and showed the improved performance than existing approaches.

• International Journal of Internet, Broadcasting and Communication
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• v.16 no.2
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• pp.1-9
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• 2024

As the Internet of Things (IoT) continues to permeate every facet of modern life, the imperative to secure this vast and dynamic frontier becomes increasingly paramount. This presents a comprehensive exploration of the challenges and opportunities inherent in safeguarding the interconnected web of IoT devices. The research critically examines the limitations of current cybersecurity measures through an extensive review of diverse topics, including IoT network performance, smart grid security, and the escalating cyber threats against critical infrastructures. A meticulous analysis of research findings underscores the need for enhanced infrastructure and ongoing research to fortify the cybersecurity mechanisms surrounding IoT objects. We underline the imperative of relentless research efforts to parry the advancing threats and leverage the promise of nascent technologies. Our findings affirm the pivotal influence of robust cybersecurity measures in crafting a resiliently connected ecosystem. The paper underscores the importance of ongoing research to address evolving threats and harness the potential of emerging technologies, reaffirming the central role of cybersecurity in shaping a secure interconnected world. In conclusion, the study emphasizes the dynamic and ever-evolving nature of cybersecurity on the IoT frontier. It unveils a complex landscape of challenges, ranging from network performance intricacies to the security concerns of critical infrastructures.

• Electronics and Telecommunications Trends
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• v.37 no.6
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• pp.43-53
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• 2022

Message Passing Interface (MPI) collective communication has been applied to various science and engineering area such as physics, chemistry, biology, and astronomy. The parallel computing performance of the data-intensive workload in the above research fields depends on the collective communication performance. To overcome this limitation, MPI collective communication technology has been extensively researched over the last several decades to improve communication performance. In this paper, we provide a comprehensive survey of the state-of-the-art research performed on the MPI collective communication and examine the trends of recently developed technologies. We also discuss future research directions for providing high performance and scalability to large-scale MPI applications.

• Journal of the Korea Institute of Military Science and Technology
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• v.12 no.3
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• pp.396-405
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• 2009

The experimental research was conducted to setup a performance prediction logic for the regenerative cooling system on a small scale liquid rocket engine using kerosene and LOX. Total heat flux of the combustion gas side was determined for the flow rate of the coolant, combustion pressure using the calorimeter thrust chamber. Based on the experimental investigation, a performance prediction scheme for the regenerative cooling system is setup in our own way. A performance prediction logic for the regenerative cooling system has been developed by the correction scheme of the combustion gas side. The key parameters determining the temperature limitation of the coolant are the mass flow rate of the coolant and the length of the combustion chamber and the nozzle. And the parameters to control the limitation of the usable wall temperature are the number of channels and wall thickness.

• ETRI Journal
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• v.27 no.5
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• pp.497-503
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• 2005

In this paper, we present a performance analysis for an MPEG-4 video codec based on the on-chip network communication architecture. The existing on-chip buses of system-on-a-chip (SoC) have some limitation on data traffic bandwidth since a large number of silicon IPs share the bus. An on-chip network is introduced to solve the problem of on-chip buses, in which the concept of a computer network is applied to the communication architecture of SoC. We compared the performance of the MPEG-4 video codec based on the on-chip network and Advanced Micro-controller Bus Architecture (AMBA) on-chip bus. Experimental results show that the performance of the MPEG-4 video codec based on the on-chip network is improved over 50% compared to the design based on a multi-layer AMBA bus.

• ETRI Journal
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• v.32 no.1
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• pp.93-101
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• 2010

A true random number generator (TRNG) is widely used to generate secure random numbers for encryption, digital signatures, authentication, and so on in crypto-systems. Since TRNG is vulnerable to environmental changes, a deterministic function is normally used to reduce bias and improve the statistical properties of the TRNG output. In this paper, we propose a linear corrector for secure TRNG. The performance of a linear corrector is bounded by the minimum distance of the corresponding linear error correcting code. However, we show that it is possible to construct a linear corrector overcoming the minimum distance limitation. The proposed linear corrector shows better performance in terms of removing bias in that it can enlarge the acceptable bias range of the raw TRNG output. Moreover, it is possible to efficiently implement this linear corrector using only XOR gates, which must have a suitable hardware size for embedded security systems.