• 한국광학회지
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• 제17권6호
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• pp.493-499
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• 2006

Modified Airy 함수를 이용하여 언덕형 굴절률 분포를 갖는 HOF를 해석하였으며, 정교한 결과를 갖는 고유 방정식을 도출하였다. 언덕형 HOF의 경우 기존의 계단형 HOF에 비하여 중공 영역 내 감쇠 전계의 기울기를 임의로 가파르게 조절할 수 있음을 보였다.

• Child Health Nursing Research
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• 제22권4호
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• pp.336-345
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• 2016

Purpose: This study was conducted to describe health in optimal fitness (HOF) in young children born prematurely and to analyze factors affecting HOF in health status, investment resources, and anthropological values, based on HOF theory. Methods: A case-control study of 76 children with preterm births (PTB) was conducted at 24 to 42 months of corrected age. Their HOF status was evaluated based on height, weight, head circumference, and the Korean-Bayley Scale of Infant Development-II and classified as either HOF-achieved or HOF-uncertain in the domain of growth, development, and all together. Results: For growth, development, and all, 26.3%, 27.6%, and 47.4% of children, respectively, belonged to the HOF-uncertain group. Logistic regression analysis showed that longer length of hospital stay (${\geq}21days$; OR=7.8; 95% CI [1.5, 40.5]), worse scores on the Home Observation for Measurement of the Environment (HOME) (${\geq}38$; OR=0.1; 95% CI [0.0, 0.4]), having a working mother, (OR=5.7; 95% CI [1.2, 27.6]), and an older mother (${\geq}35years$; OR=8.8; 95% CI [2.1, 37.3]) were statistically significant contributors of HOF-uncertain in the domain of all. Conclusion: Findings show that young children born prematurely with prolonged stays in a neonatal intensive care unit and insufficient socioeconomic resources at home are more likely to exhibit delayed growth and development.

• Current Optics and Photonics
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• 제2권3호
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• pp.226-232
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• 2018

We propose a triangular-multicore hollow optical fiber (TMC-HOF) design for uncoupled mode-division and space-division multiplexing. The TMC-HOF has three triangular cores, and each core has three modes: $LP_{01}$ and two split $LP_{11}$ modes. The asymmetric structure of the triangular core can split the $LP_{11}$ modes. Using the proposed structures, nine independent modes can propagate in a fiber. We use a fully vectorial finite-element method to estimate effective index, chromatic dispersion, differential group delay (DGD), and confinement loss by controlling the parameters of the TMC-HOF structure. We confirm that the proposed TMC-HOF shows flattened chromatic dispersion, low DGD, low confinement loss, low core-to-core crosstalk, and low crosstalk between adjacent modes. The proposed TMC-HOF can provide a common platform for MDM and SDM applications.

• 한국광학회지
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• 제21권5호
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• pp.200-205
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• 2010

본 논문에서는 포토닉 밴드갭 광섬유(Photonic Bandgap Fiber: PBGF) 사이에 중공광섬유(Hollow Optical Fiber: HOF)를 융착 접속시켜 만든 광섬유 간섭계와 넓은 모드 면적을 가지는 광자결정 광섬유(Large Mode Area-Photonic Crystal Fiber: LMA-PCF)사이에 HOF를 융착접속시켜 만든 광섬유 간섭계의 온도 및 스트레인에 대한 광학적 특성을 분석하였다. PBGF 또는 LMA-PCF와 HOF의 융착접속시 광섬유내 공기구멍을 최대한 유지하도록 융착조건을 최적화하여 접속 손실을 줄였다. PBGF와 HOF로 구성된 광섬유 간섭계의 온도 및 스트레인에 대한 민감도는 각각 15.4 pm/$^{\circ}C$와 0.24 pm/${\mu}\varepsilon$으로 측정되었으며, LMA-PCF와 HOF로 구성된 광섬유 간섭계의 온도 및 스트레인에 대한 민감도는 각각 17.4 pm/$^{\circ}C$와 0.2 pm/${\mu}\varepsilon$으로 측정되었다.

• ETRI Journal
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• 제44권3호
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• pp.361-378
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• 2022

In 5G, the required target for interruption time during a handover (HO) is 0 ms. However, when a handover failure (HOF) occurs, the interruption time increases significantly to more than hundreds of milliseconds. Therefore, to fulfill the requirement in as many scenarios as possible, we need to minimize HOF rate as close to zero as possible. 3GPP has recently introduced conditional HO (CHO) to improve mobility robustness. In this study, we propose "ZEro handover failure with Unforced and automatic time-to-execute Scaling" (ZEUS) algorithm to optimize HO parameters easily in the CHO. Analysis and simulation results demonstrate that ZEUS can achieve a zero HOF rate without increasing the ping-pong rate. These two metrics are typically used to assess an HO algorithm because there is a tradeoff between them. With the introduction of the CHO, which solves the tradeoff, only these two metrics are insufficient anymore. Therefore, to evaluate the optimality of an HO algorithm, we define a new integrated HO performance metric, mobility-aware average effective spectral efficiency (MASE). The simulation results show that ZEUS provides higher MASE than LTE and other CHO variants.

• 대한지리학회:학술대회논문집
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• 대한지리학회 2002년도 춘계학술대회 요약집
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• pp.69-72
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• 2002

• 한국통신학회논문지
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• 제35권6A호
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• pp.538-546
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• 2010

This paper presents an overview of position-based routing algorithms. We analyze performances of routing algorithms such as Hybrid Opportunistic Forwarding (HOF), Opportunistic multi-hop routing (ExOR), Location based Geocasting and Forwarding (LGF), and Greedy Forwarding in nearest with forward Progress (GFP) routing algorithms to find the best one in terms of packet error rate and throughput efficiency over effects of fading and noise variance in wireless networks. The analyses in closed form expressions are confirmed by the simulation results, which fully agree to analysis results. Additionally, the simulation results indicate significant differences among algorithms when varying the average SNR or the number of relays.

• Journal of Computing Science and Engineering
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• 제9권1호
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• pp.29-38
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• 2015

Human action recognition has become an important research topic in computer vision area recently due to many applications in the real world, such as video surveillance, video retrieval, video analysis, and human-computer interaction. The goal of this paper is to evaluate descriptors which have recently been used in action recognition, namely Histogram of Oriented Gradient (HOG) and Histogram of Optical Flow (HOF). This paper also proposes new descriptors to represent the change of points within each part of a human body, caused by actions named as Histogram of Changing Points (HCP) and so-called Average Speed (AS) which measures the average speed of actions. The descriptors are combined to build a strong descriptor to represent human actions by modeling the information about appearance, local motion, and changes on each part of the body, as well as motion speed. The effectiveness of these new descriptors is evaluated in the experiments on KTH and Hollywood datasets.

• ETRI Journal
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• 제37권6호
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• pp.1065-1076
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• 2015

Network densification is regarded as the dominant driver for wireless evolution into the era of 5G. However, in this context, interference-limited dense small cell deployments are facing technical challenges in mobility management. The recently announced results from an LTE field test conducted in a dense urban area show a handover failure (HOF) rate of over 21%. A major cause of HOFs is the transmission failure of handover command (HO CMD) messages. In this paper, we propose two enhancements to HO performance in LTE networks - radio link failure-proactive HO, which helps with the reliable transmission of HO CMD messages while the user equipment is under a poor radio link condition, and Early Handover Preparation with Ping-Pong Avoidance (EHOPPPA) HO, which assures reliable transmission of HO CMD under a good radio link condition. We analyze the HO performance of EHOPPPA HO theoretically, and perform simulations to compare the performance of the proposed schemes with that of standard LTE HO. We show that they can decrease the HOF rate to nearly zero through an analysis, and based on the simulation results, by over 70%, without increasing the ping-pong probability.

• 한국식품영양과학회지
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• 제20권2호
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• pp.111-120
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• 1991

가열유 섭취에 따른 동물체내에서의 과산화적 손상에 대한 연구와 VE의 식이중 첨가수준에 따라 가열유로 인한 과산화적 손상에 대한 항산화적 방어현상을 관찰하기 위하여 열화된 가열유(산가 4.02, carbonyl가 27.9, peroxide value 52.7)를 하루 총열량의 10%, 그리고 $dl-{\alpha}-tocopheryl acetate$의 양을 달리하여 (0, 40, 200mg/kg of diet : HOF group, HO group, HOE group) tube feeding하면서 0, 3, 6주간씩 사육하였다. 실험종료후 쥐를 휘생시켜 간장을 적출하여 과산화적 손상으로부터 생체를 보호하는 생체내 항산화적 해독기전에 관여하는 효소계인 superoxide dismutase(SOD), glutathione peroxidase(GPX)와 비효소적 방어계인 microsome 대의 VE를 측정함과 동시에 조직의 손상이나 노화의 독성이 되는 지질과산화량을 측저 였고 또한 mitochondria를 비롯한 세포내 각 소기관들의 손상을 전자현미경적으로 관찰하였다. SOD활성도는 가열유 투여군이 대조군에 비해 다소 높았고 GPX활성도 및 VE함량0] 낮았으며 POV는 현저하게 높았다. 전자현미경적 관찰에서는 mitochondria내막과 cristae가 소실되고 핵막과 chromatin이 불규칙 하였다. 가열유 투여군에서 VE첨가수준을 각각 달리했을때 VE가 부족한 HOF식이군은 HO군, HOE군에 비해 s SOD활성이 높았고, GPX활성 및 VE함량이 현저히 저하되었으며, POV가 높았으며, 세포내 mitochon ndria등을 비롯한 소기관들의 손상이 더욱 현저하게 나타났으나, VE를 다량 첨가한 HOE식이군에서는 HO군, HOF식이군에 비해 이러한 과산화적 손상이 경하게 나타냈다. 또 이러한 현상은 3주때보다 6주에서 더 뚜렷하게 나타났다.