• Journal of Communications and Networks
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• v.14 no.4
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• pp.352-363
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• 2012

In this paper, we study the role of cooperative relays to provide and improve secure communication rates through decodeand-forward (DF) strategies in a full-duplex multiple relay network with an eavesdropper. We consider the DF scheme as a basis for cooperation and propose several strategies that implement different versions of this scheme suited for cooperation with multiple relays. Our goal is to give an efficient cooperation paradigm based on the DF scheme to provide and improve secrecy in a multiple relay network. We first study the DF strategy for secrecy in a single relay network. We propose a suboptimal DF with zero forcing (DF/ZF) strategy for which we obtain the optimal power control policy. Next, we consider the multiple relay problem. We propose three different strategies based on DF/ZF and obtain their achievable secrecy rates. The first strategy is a single hop strategy whereas the other two strategies are multiple hop strategies. In the first strategy, we show that it is possible to eliminate all the relays' signals from the eavesdropper's observation (full ZF), however, the achievable secrecy rate is limited by the worst source-relay channel. Our second strategy overcomes the drawback of the first strategy, however, with the disadvantage of enabling partial ZF only. Our third strategy provides a reasonable compromise between the first two strategies. That is, in this strategy, full ZF is possible and the rate achieved does not suffer from the drawback of the first strategy. We conclude our study by a set of numerical results to illustrate the performance of each of the proposed strategies in terms of the achievable rates in different practical scenarios.

• Journal of Animal Science and Technology
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• v.59 no.1
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• pp.1.1-1.11
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• 2017

Background: Intrauterine environment plays a pivotal role in the origin of fatal diseases such as the metabolic syndrome. Diabetes is associated with low-grade inflammatory state and dysregulated adipokines production. The aim of this study is to investigate the effect of maternal diabetes on adipocytokines (adiponectin, leptin and TNF-${\alpha}$) production in F1 offspring in rats. Methods: The offspring groups were as follows: F1 offspring of control mothers under control diet (CD) (CF1-CD), F1 offspring of control mothers under high caloric diet (HCD) (CF1-HCD), F1 offspring of diabetic mothers under CD (DF1-CD), and F1 offspring of diabetic mothers under HCD (DF1-HCD). Every 5 weeks post-natal, 10 pups of each subgroup were culled to obtain blood samples for biochemical analysis. Results: The results indicate that DF1-CD and DF1-HCD groups exhibited hyperinsulinemia, dyslipidemia, insulin resistance and impaired glucose homeostasis compared to CF1-CD (p > 0.05). DF1-CD and DF1-HCD groups had high hepatic and muscular depositions of TGs. The significant elevated NEFA level only appeared in offspring of diabetic mothers that was fed HCD. DF1-CD and DF1-HCD groups demonstrated low serum levels of adiponectin, high levels of leptin, and elevated levels of TNF-${\alpha}$ compared to CF1-CD (p > 0.05). These results reveal the disturbed metabolic lipid profile of offspring of diabetic mothers and could guide further characterization of the mechanisms involved. Conclusion: Dysregulated adipocytokines production could be a possible mechanism for the transgenerational transmittance of diabetes, especially following a postnatal diabetogenic environment. Moreover, the exacerbating effects of postnatal HCD on NEFA in rats might be prone to adipcytokine dysregulation. Furthermore, dysregulation of serum adipokines is a prevalent consequence of maternal diabetes and could guide further investigations to predict the development of metabolic disturbances.

• Journal of the Korean Chemical Society
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• v.29 no.6
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• pp.592-598
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• 1985

The total vibrational deexcitation rate constants $k_{v,v-1}$ of HF(v = 5-7) by HF(${\mu}$ = 0) and DF(${\mu}$ = 9-12) by DF(${\mu}$= 0) including both the vibration to vibration (V ${\to}$ V) and vibration to rotation and translation (V ${\to}$ R, T) energy transfer channels have been calculated semiclas-sically using a simplified collision model. The calculated results are in reasonably good agreement with those obtained by experimental and other theoretical studies. The rate constants increase with increasing temperature and also with increasing v. They also show that the relaxation of the highly excited HF and DF occurs predominantly via the V ${\to}$ R, T path at low temperature. The effectiveness of the V ${\to}$ V path, however, increases as the temperature is raised.

• Land and Housing Review
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• v.14 no.2
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• pp.97-107
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• 2023

This study examined how to better provide quality temporary housing for people in the event of natural and social disasters. Design for Manufacture and Assembly (DfMA) is suitable for creating an efficient planning model for the mass production and transport of a modular house. The proposed DfMA model has the following three characteristics. First is the division of the modular house into service modules and functional modules and to create diversity by developing standard parts and multi-functional parts. Second is a flexible layout suitable for various site conditions. Such flexible layouts would allow identical homes to be mass produced and deployed to a variety of locations, both nationally and internationally. Third is to simplify and minimize the automation process with dry construction to increase production efficiency. Application of this DfMA design method can lead to reduced construction time and cost and improve housing quality.

• Proceedings of the IEEK Conference
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• 2008.06a
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• pp.373-374
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• 2008

This paper proposes an architecture for high-speed data processing of the DF-DPD. The DF-DPD have the architecture feedbacking the detected phase to reduce the noise of the previous symbol as phase reference. However, the feedback of the detected phase results in lower data processing speed than that of the conventional differential phase detection. In this paper, an architecture is proposed for high-speed data processing of the differential phase detectors with decision feedback in the DF-DPD.

• Biomedical Science Letters
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• v.8 no.4
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• pp.269-273
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• 2002

Dengue fever (DF) is an acute febrile illness caused by dengue viruses in the family Flaviviridae, genus Flavivirus. DF has so far posed any problem in Korea, however it has been recently believed to be associated with oversea's traveler infected with dengue virus. Antibody titers of sera from DF patients against dengue virus were measured by indirect immunofluorescence assay (IFA) and plaque reduction neutralization test (PRNT), including the haematologic test. Three of patients with DF showed highly fluorescent and neutralizing antibody titers by IFA and PRNT assay. Two of them showed higher, remarkably. Meanwhile, one of them was tested and resulted in severe tirombocytopenia, elevated serum levels of aspartate aminotransferase (AST), alanine aminotransferase (ALT) activities as well as mild leucopenia, increased monocytes and basophils and depressed lymphocytes in haematological differential count.

• Food Science and Biotechnology
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• v.15 no.1
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• pp.70-76
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• 2006

Anti-obesity effect of biocellulose and diet formulation containing it was evaluated using obese rats. Thirty male Sprague-Dawlely (SD) rats were randomly assigned to high-fat diet group (CON), high-fat diet group containing 5% biocellulose (BIO), and high-fat diet group containing 5% dietary formulation (DF). After 10 weeks, body weight gains of BIO and DF groups were reduced by 15.1 and 6%, respectively, as compared with CON group. Epididymus, parirenal, and visceral fat pads of BIO and DF groups were lower than those of CON group. Weight of interscapular brown adipose tissues increased slightly in BIO group and significantly in DF group. Size of adipocyte in rats decreased in BIO and DF groups. Results indicate biocellulose-containing diet has anti-obesity effect by reducing body weight gain and white adipocytes depots in rats fed high-fat diet.

• Proceedings of the Korean Association of Geographic Inforamtion Studies Conference
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• 2008.06a
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• pp.75-81
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• 2008

오늘날 정부기관, 지자체 그리고 민간 기업 에서 3차원 지리정보데이터에 대한 필요성이 증가하고 있어 그에 대한 연구가 활발히 이루어지고 있다. 이러한 연구의 결과로 국내에서 3차원 지리정보 데이터 포맷인 3DF-GML(3DFeature-GML)이 개발되었다. 하지만 3DF-GML의 데이터는 기존의 Shape 파일만을 사용하여 구축되기 때문에 활용성에 제한을 받고 있다. 또한 제작 및 수정 시에는 제한된 애플리케이션 활용만이 허용된다. 이에 따라 3DF-GML의 활용성을 높이기 위해 국내의 데이터뿐 만이 아니라 국외에서 제작되어진 3차원 지리정보 데이터 포맷의 데이터를 활용할 수 있는 방안이 필요하다. 본 논문에서는 국내의 3차원 지리정보 포맷(3DF-GML)과 국외의 3차원 지리정보 포맷들간의 데이터 포맷을 비교 및 분석한다. 이러한 분석은 국외 3차원 지리정보 포맷의 데이터 활용 및 호환을 유도하는 것이 가능하다. 따라서 본 논문에서는 국내 3차원 지리 정보데이터(3DF-GML)와 국외 3차원 지리정보 데이터 간의 변환 규칙 및 방법을 제시한다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.15 no.1
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• pp.365-382
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• 2021

This paper proposes a novel two-way relaying (TWR) approach for a two-relay wireless network based on non-orthogonal multiple access (NOMA), where two terminals exchange messages with a cellular base station (BS) via two intermediate relay stations (RSs). We propose a NOMA-based TWR approach with two relaying schemes, i.e., amplify-and-forward (AF) and decode-and-forward (DF), referred to as NOMA-AF and NOMA-DF. The sum-rate performance of our proposed NOMA-AF and NOMA-DF is analyzed. A closed-form sum-rate upper bound for the NOMA-AF is obtained, and the exact ergodic sum-rate of NOMA-DF is also derived. The asymptotic sum-rate of NOMA-AF and NOMA-DF is also analyzed. Simulation results show that the proposed scheme outperforms conventional orthogonal multiple access based transmission schemes. It is also shown that increasing the transmit power budget of the relays only cannot always improve the sum-rates.

• Journal of KIBIM
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• v.12 no.1
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• pp.10-22
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• 2022

Prefabricated bridges require strict management of tolerance during fabrication and assembly. In this paper, digital engineering models for prefabricated bridge components such as deck, girder, pier, abutment are suggested to support information delivery through the life-cycle of the bridge. Rule-based modeling is used to define geometry of the members considering variable dimensions due to fabrication and assembly error. DfMA(design for manufacturing and assembly) provides the rules for ease of fabrication and assembly. The digital engineering model consists of geometry, constraints and corresponding parameters for each phase. Alignment and control points are defined to manage tolerances of the prefabricated bridge during fabrication and assembly. Quality control by digital measurement of dimensions was also considered in the model definition. A pilot bridge was defined virtually to validate the suggested digital engineering models. The digital engineering models for DfMA showed excellent potential to realize prefabricated bridges.