• 디지털콘텐츠학회 논문지
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• 제16권3호
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• pp.417-424
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• 2015

산업의 고도화 및 새로운 기계의 도입, 화학물질 사용 등 산업재해의 다양한 양상과 더불어 생산설비들의 자동화, 대형화로 인해 산업재해 발생의 양상이 점차 다양해지고 있다.국내 산업재해는 OECD(Organization for Economic Cooperation and Development) 경제협력개벌기구대비, 상대적 하위수준에 있어 기업 발생 산업재해는 근로자들의 심리적 및 치료와 보상 손실에도 타격이 되어 기업 총 생산과 이윤 추구에도 중요문제가 야기되고 있다. 더불어, 장애자와 사망유족들의 증가로 생활 안정문제 등 사회적 문제도 제기된다. 이러한 동기에서 본 논문은 산업재해 통계와 산재예방사업을 분석하고, 시스템다이내믹스 법론을 이용하여 산업재해율을 예측하고 평가하는 모델을 개발하였다. 모델은 근로자수 모델, 재해자수 모델, 재해율 모델 등 총 12개의 모델로 구성되었고, 규모별 분석에서는 근로자수를 기준으로 12개 그룹으로, 업종별 분석에서는 제조업, 건설업 등 총 10개의 업종으로 구분하여 개발하였다. 개발된 모델을 토대로 업종별 규모별 산업재해율을 예측하고 산재예방사업을 다각도로 평가하는 방법론을 제시하였다.

• 복식
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• 제55권8호
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• pp.15-29
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• 2005

In these days, T-shirt is not only the simple wearing goods but also the suggestive communication, which is not showed outward as well as being intended. Also, it indicates expression of contemporary sensitive living, expression of substantial oneself, and the effective commercial promotion fer advertising fashion brand and promoting the object's sale. Following the above concept, the aim of this study is to understand the outstanding tendency of ' The T-shirt one-point graphic's functions and visual image ', which is appeared after 2001 in the fashion industry's commercial aspects. The visual image's applicative rate of the T-shirt one point graphic is the following; The best applicative rate on T-shirt one- point graphic is the visual image using the mix & match technique shown 42.8 percent applicative rate. The second one is the visual image using the typography shown 38.7 percent. The third one is the visual image using the animals and plants shown 8.5 percent. The fourth one is the visual image using the person's character shown 3.8 percent. The fifth one is the visual image using the geometry shown 2.4 percent. The least one is the visual image using the cartoon character shown 1.6 percent. On the other hand, another important function of t-shirt one-point graphic is the following; 1, The essential function as t-shirt design factor. 2, The promotional function as brand image marketing and brand advertisement. 3. The communicative function as discriminative strategy of object. 4. The achievable function as value added goods.

• Journal of Positioning, Navigation, and Timing
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• 제5권4호
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• pp.221-233
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• 2016

This paper deals with performance assessment of the kinematic network-based GPS positioning technique with a view to using it for ellipsoidally referenced bathymetric surveys. To this end, two field trials were carried out on a land vehicle and a surveying vessel. Single-frequency GPS data acquired from these tests were processed by an in-house software which equips the network modeling algorithm with instantaneous ambiguity resolution procedure. The results reveals that ambiguity success rate based on the network model is mostly higher than 99.0%, which is superior to that of the single-baseline model. In addition, achievable accuracy of the technique was accessed at ${\pm}1.6cm$ and 2.7 cm with 95% confidence level in horizontal and vertical component respectively. From bathymetric survey at the West Nakdong River in Busan, Korea, 3-D coordinates of 2,011 points on its bed were computed by using GPS-derived coordinates, attitude, measured depth and geoid undulation. Note that their vertical coordinates are aligned to the geoid, the so-called orthometric height which is widely adopted in river engineering. Bathymetry was constructed by interpolating the coordinate set, and some discussion on its benefit was given at the end.

• 한국지열·수열에너지학회논문집
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• 제9권3호
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• pp.1-10
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• 2013

Open loop geothermal heat pumps have great potential where the groundwater resources are sufficient. Performance of open loop geothermal heat pump systems is considered higher than that of ground source heat pumps. Head and power calculation of submersible pumps, heat pump units, and piping are numerically based on regression data. Results shows that the system performance drops as the water level drops, and the lowest flow rates generally achieve the highest system COPs. The highest achievable cooling system COPs become 6.34, 6.12, and 5.95 as the groundwater levels are 5m, 15m, and 25m. The highest heating system COPs also become 4.59, 4.37, and 4.20. Groundwater level and submersible pump selection greatly influence the system performance of open loop geothermal heat pumps. It needs to be analysed during the design process of open loop geothermal heat pump system, possibly with analysis tools that include wide range of pump product data.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제13권4호
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• pp.1961-1974
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• 2019

In this letter, a harmonic-mean-based dual-antenna selection scheme at relay node is proposed in two-way relaying networks (TWRNs). With well-designed distributed orthogonal concatenated Alamouti space-time block code (STBC), a dual-antenna selection problem based on the instantaneous achievable sum-rate criterion is formulated. We propose a low-complexity selection algorithm based on the harmonic-mean criterion with linearly complexity $O(N_R)$ rather than the directly exhaustive search with complexity $O(N^2_R)$. From the analysis of network outage performance, we show that the asymptotic diversity gain function of the proposed scheme achieves as $1/{\rho}{^{N_R-1}}$, which demonstrates one degree loss of diversity order compared with the full diversity. This slight performance gap is mainly caused by sacrificing some dual-antenna selection freedom to reduce the algorithm complexity. In addition, our proposed scheme can obtain an extra coding gain because of the combination of the well-designed orthogonal concatenated Alamouti STBC and the corresponding dual-antenna selection algorithm. Compared with the common-used selection algorithms in the state of the art, the proposed scheme can achieve the best performance, which is validated by numerical simulations.

• 융합정보논문지
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• 제10권10호
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• pp.24-31
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• 2020

비직교 다중 접속에서 약 채널 사용자의 저하된 성능은 문제로 제기되고 있다. 본 논문에서는, 수용 가능한 정도의 강 채널 사용자의 BER 손실로, 비직교 다중 접속의 약 채널 사용자의 BER 성능을 향상시키기 위해, 비대칭 2PAM을 제안한다. 먼저, 비대칭 2PAM을 설계하고, 총 할당 전력을 계산한 후, 제안된 기법의 BER에 대한 폐쇄형 수식을 구한다. 다음, 강 채널 사용자의 적은 BER 저하로, 약 채널 사용자의 BER이 향상되었음을 보여준다. 또한, 강 채널 사용자의 3 dB 의 SNR 저하로 약 채널 사용자의 SNR 이득이 10 dB 에 달하는 것을 보여줌으로서 제안된 기법의 우수성을 입증한다. 결과적으로, 5G 시스템의 비직교 다중 접속에서 비대칭 2PAM이 고려될 수도 있다. 향후 연구 주제로서, 제안된 기술에 대한 최대 전송률을 분석하는 것은 의미있는 연구일 수 있다.

• 한국통신학회논문지
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• 제27권10A호
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• pp.962-968
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• 2002

무선통신 환경의 한정된 주파수 자원에서 신뢰성 있는 고속의 통신방식이 요구되고 있다. 직교 진폭 변조 (QAM) 는 대역폭의 증가없이 고속의 데이터 처리가 가능한 유용한 변조 방식이다. 이제까지 사각형(rectangular) 직교 진폭 변조 (R-QAM) 신호의 일반화된 BER 식은 유도된바 없다. 이 논문에서는 가산성 백색 가우시안 잡음 환경에서 그레이 부호화된 R-QAM의 일반화된 closed-from 형태의 EBR식을 유도하고 분석한다. 먼저 I-ary PAN 신호에 대하여 Irk 4, 8, 16 일 때의 유도하고 이 결과들로부터 유도 과정의 규칙성을 찾아내며, 그 규칙성들로부터 임의의 I-ary PAM 신호에 대한 일반화된 BER 식을 유도한다. R-QAM 신호는 각각 독립적인 동상 성분의 I-ary PAM 과 직교 성분의 J-ary PAM으로 구성되기 때문에 I-ary PAM 의 일반화된 BER 식으로부터 R-QAM 신호에 대한 일반화된 BER 식을 구한다. 또한 SNR이 높을 때에 지배적인 항을 고려한 간단한 근사식도 유도한다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제16권9호
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• pp.3172-3193
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• 2022

Cognitive radio-simultaneous wireless information and power transfer (CR-SWIPT) has attracted much interest since it can improve both the spectrum and energy efficiency of wireless networks. This paper focuses on the resource sharing between a point-to-point primary system (PRS) and a multiuser multi-antenna cellular cognitive radio system (CRS) containing a large number of cognitive users (CUs). The resource sharing optimization problem is formulated by jointly scheduling CUs and adjusting the transmit power at the cognitive base station (CBS). The effect of accessing CUs' spatial channel correlation on the possible transmit power of the CBS is investigated. Accordingly, we provide a low-complexity suboptimal approach termed the semi-correlated semi-orthogonal user selection (SC-SOUS) algorithm to enhance the spectrum efficiency. In the proposed algorithm, CUs that are highly correlated to the information decoding primary receiver (IPR) and mutually near orthogonal are selected for simultaneous transmission to reduce the interference to the IPR and increase the sum rate of the CRS. We further develop a spatial correlation-based resource sharing (SC-RS) strategy to improve energy sharing performance. CUs nearly orthogonal to the energy harvesting primary receiver (EPR) are chosen as candidates for user selection. Therefore, the EPR can harvest more energy from the CBS so that the energy utilization of the network can improve. Besides, zero-forcing precoding and power control are adopted to eliminate interference within the CRS and meet the transmit power constraints. Simulation results and analysis show that, compared with the existing CU selection methods, the proposed low-complex strategy can enhance both the achievable sum rate of the CRS and the energy sharing capability of the network.

• Journal of Microbiology and Biotechnology
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• 제18권11호
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• pp.1773-1784
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• 2008

Effects of various industrially important carbon sources (glucose, sucrose, xylose, gluconate, and glycerol) on shikimic acid (SA) biosynthesis in Escherichia coli were investigated to gain new insight into the metabolic capability for overproducing SA. At the outset, constraints-based flux analysis using the genome-scale in silico model of E. coli was conducted to quantify the theoretical maximum SA yield. The corresponding flux distributions fueled by different carbon sources under investigation were compared with respect to theoretical yield and energy utilization, thereby identifying the indispensable pathways for achieving optimal SA production on each carbon source. Subsequently, a shikimate-kinase-deficient E. coli mutant was developed by blocking the aromatic amino acid pathway, and the production of SA on various carbon sources was experimentally examined during 51 batch culture. As a result, the highest production rate, 1.92 mmol SA/h, was obtained when glucose was utilized as a carbon source, whereas the efficient SA production from glycerol was obtained with the highest yield, 0.21 mol SA formed per mol carbon atom of carbon source consumed. The current strain can be further improved to satisfy the theoretically achievable SA production that was predicted by in silico analysis.

• 서비스연구
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• 제6권4호
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• pp.59-74
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• 2016

본 연구의 목적은 주가연계사채(ELB)의 제시수익률에 대해 달성가능 정도를 분석하여 ELB 문제점을 도출하고, ELB 투자방안에 대한 방향성을 제시하고자 한다. 연구방법은 2015~2016년에 발행된 ELB 구조를 2010년 1월부터 2016년 6월까지 추정수익률을 분석하며, 최소보장수익률, 최고한도율, 참여율과 실제수익률 간의 상관관계와 회귀분석을 실시한다. 분석결과는 주가상승률이 최고상승률 한도를 벗어나지 않아서 주가상승률에 의해서 은행금리수준보다 높은 2%이상의 수익률을 달성할 확률은 20%에도 미치지 못하며, ELB 상품의 평균추정수익률은 1.49%에 불과하여 은행의 2015년 수신금리인 1.72% 보다 낮아서 ELB의 실현가능수익률이 기대치에 미치지 못한다. 최소보장수익율과 ELB 수익률의 상관계수는 0.843, 최고한도수익율과 ELB 수익률의 상관계수는 0.279로 산출되어 ELB 수익률과 최소보장수익율 간에 상관관계는 매우 높다. 시사점은 ELB 실제수익률이 은행예금금리 보다 높지 않으며, 주가상승률이 최고한도 이내에 있을 확률이 낮을 것이다.