• Korean Journal of Food Science and Technology
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• v.47 no.3
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• pp.373-379
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• 2015

This study aimed to investigate the anti-amnesic effect of perilla oil against trimethyltin (TMT)-induced learning and memory impairment in ICR mice. Perilla oil (2.5 mL/kg of body weight) and soybean oil (2.5 mL/kg of body weight) were administered orally to mice for 3 weeks, and at the end of the experimental period, cognitive behavior was examined by Y-maze and Morris water maze (MWM) tests. Behavioral tests showed that the mice treated with perilla oil had improved cognitive function compared to that in mice administered soybean oil. Analysis of brain tissue showed that perilla oil significantly lowered acetylcholinesterase activity and malondialdehyde (MDA) levels. Oxidized glutathione (GSH)-to-total GSH ratio also decreased from 10.4% to 5.3% in perilla oil-treated mice, but superoxide dismutase (SOD) activity increased from 11.7 to 14.2 U/mg protein. Therefore, these results suggest that the perilla oil could be a potential functional substance for improving cognitive function.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.4A
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• pp.356-368
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• 2011

While most of the public radio spectrum bands are allocated to licensed users, cognitive radio has been considered as a promising technology for the efficient spectrum utilization. In this new technology, secondary users opportunistically use the temporally underutilized licensed bands as long as they do not give the harmful interference to primary users. In this paper, we focus on the infra-structured network condition in which the cognitive radio network consists of a cognitive radio base station and multiple secondary users. Upon detecting a primary user, the entire cognitive radio network generally switches to another available channel, even if most of the on-going communications still does not interfere with the primary user. Moreover, the network re-entry process on a new channel causes the service disruption of the on-going communications. For this reason, in this paper, we propose a relaying scheme for efficient frequency usage, in which the secondary user out of the interference range of a primary user performs as a relaying node for the secondary user possibly interfering with a primary user. The entire spectrum switching is not required, and thus, we can avoid the service disruption of the on-going communications as much as possible.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.26 no.4
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• pp.296-304
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• 1993

The effects of pretreatment on the lipid oxidation of korean geoduck muscle during storage at $-20^{\circ}C$ were investigated. In the lipid compositions of geoduck muscle, neutral, glycolipid, and phospholipid contents were $46.1\%,\;4.5\%\;and\;49.5\%$, respectively. And the content of phospholipid decreased to $39.9\%$ by blanching. In the fatty acids composition, $C_{16:0},\;C_{20:5}\;and\;C_{22:6}$ fatty acids were major portions and their contents showed, respectively, $10\%$ of total fatty acids amount or more. $C_{18:0},\;C_{16:1},\;C_{18:1},\;C_{14:0}\;and\;C_{20:1}$ fatty acids were also important fatty acids and their amounts were so much as $5\%$ or more. The polyunsaturated fatty acid contents were relatively high as $39.25\%{\sim}42.60\%$. POV in RM and VM samples increased gradually and showed 3.72meq/kg, or 3.00meq/kg after 90 days storage, respectively. However, in case of samples pretreated by blanching, there was slightly increase of POV throughout storage. From the results above, it was suggested that the pretreatment of blanching was effective in retardation of lipid oxidation for the longterm storage.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.19 no.5
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• pp.162-177
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• 2020

The perception of traffic environment based on various sensors in autonomous driving system has a direct relationship with driving safety. Recently, as the perception model based on deep neural network is used due to the development of machine learning/in-depth neural network technology, a the perception model training and high quality of a training dataset are required. However, there are several realistic difficulties to collect data on all situations that may occur in self-driving. The performance of the perception model may be deteriorated due to the difference between the overseas and domestic traffic environments, and data on bad weather where the sensors can not operate normally can not guarantee the qualitative part. Therefore, it is necessary to build a virtual road environment in the simulator rather than the actual road to collect the traning data. In this paper, a training dataset collection process is suggested by diversifying the weather, illumination, sensor position, type and counts of vehicles in the simulator environment that simulates the domestic road situation according to the domestic situation. In order to achieve better performance, the authors changed the domain of image to be closer to due diligence and diversified. And the performance evaluation was conducted on the test data collected in the actual road environment, and the performance was similar to that of the model learned only by the actual environmental data.

• Journal of IKEEE
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• v.23 no.1
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• pp.280-288
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• 2019

In the CR-enabled MANET, routing paths can be easily destroyed due to node mobility and channel unavailability (due to the emergence of the PU of a channel), resulting in significant overhead to maintain/recover the routing path. In this paper, network caching is actively used for route maintenance, taking into account the properties of the CR. In the proposed scheme, even if a node detects that a path becomes unavailable, it does not generate control messages to establish an alternative path. Instead, the node stores the packets in its local cache and 1) waits for a certain amount of time for the PU to disappear; 2) waits for a little longer while overhearing messages from other flow; 3) after that, the node applies local route recovery process or delay tolerant forwarding strategy. According to the simulation study using the OPNET simulator, it is shown that the proposed scheme successfully reduces the amount of control messages for path recovery and the service latency for the time-sensitive traffic by 13.8% and 45.4%, respectively, compared to the existing scheme. Nevertheless, the delivery ratio of the time-insensitive traffic is improved 14.5% in the proposed scheme.

• Korean Journal of Ecology and Environment
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• v.56 no.4
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• pp.406-413
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• 2023

Captive breeding and reintroduction are crucial strategies for conserving endangered species populations. However, fish raised in predator-free environments, show a lack of recognition of predationrelated stimuli such as chemical and visual signals. It is critical to recognize chemical signals from injured conspecifics, also known as alarm signals, and the order or shape of predators to indicate the spread of predation risk in the habitat. We conducted a laboratory experiment to determine and adjust the optimal exposure period to induce appropriate anti-predator behavior response to different types of stimuli (Chemical, Visual and Chemical+Visual) for the endangered species Microphysogobio rapidus. Our results demonstrate that predator avoidance behavior varies depending on the types of stimuli and the duration of predation risk exposure. First, the results showed captive-breed M. rapidus show lack of response against conspecific alarm signal (Chemical cue) before the predation risk exposure period and tend to increase response over predation risk exposure time. Second, response to predator (visual cue) tend to peak at 48 hours cumulative exposure, but show dramatic decrease after 72 hours cumulative exposure. Finally, response to the mixed cue (Chemical+visual) tend to peak prior to the predation risk exposure period and show reduced response during subsequent exposure periods. This experiment confirms the lack of responsiveness to conspecific alarm signals in captive-bred M. rapidus and the need for an optimal nature behavior enhancement program prior to release of endangered species. Furthermore, responsiveness to predator visual signal peak at 48 hours cumulative exposure, suggest an optimal predation risk exposure period of up to 48 hours.

• Proceedings of the Acoustical Society of Korea Conference
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• autumn
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• pp.207-212
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• 1999

본 논문에서는 공간에 위치한 음원으로부터 양 귀에 들리는 음향을 좌우 대칭형 스피커를 이용하여 재현하는 기술에 대한 문제점, 즉 좌우 스피커와 양 귀의 음압전달 특성에 수반되는 Cross-talk 제거와 음향학적 모델 선정에 대한 문제점들을 우선 소개한다. 이러한 문제점을 해결할 수 있는 Transaural 필터의 모델 제시와 본 모델의 음향학적 특성을 고찰한다. 본 연구에서는 인간 청각 기관의 공간 인지량적 인자인 ILB(interaural Level Difference)와 ITD(Tnteraural Time Difference)의 개념을 이용한 새로운 Cross-talk 제거 방법과 그리고 청각기관의 "Masking" 특성을 이용한 Transaural 필터의 진폭 보상 방법을 새로이 제안한다. 끝으로 제안된 기법은 음색 왜곡과 음질 저하를 최소화할 수 있는 장점 뿐 아니라 현장 음향 기사들이 직접 음향제작에 적용할 수 있는 장점 또한 제공한다.

• Electronics and Telecommunications Trends
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• v.29 no.2
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• pp.49-59
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• 2014

모바일 트래픽 폭증으로 인한 망 과부하와 서비스 품질 저하 이슈가 부각되면서 이에 대한 해결 방안으로 스몰셀이 새롭게 부상하고 있다. 전 세계적으로 스몰셀을 도입하는 사업자 수가 빠르게 증가하고 있으며 글로벌 장비업체뿐만 아니라 다양한 제조업체들이 스몰셀 시장에 진출하였다. 2014년에도 스몰셀 수요 증대 및 인지도 향상, 대규모 서비스 전개 등이 스몰셀 시장의 성장을 이끌 것으로 예상된다. 이러한 확산 추세에 힘입어 스몰셀은 향후 우회망 역할을 넘어 다양한 유무선 융합서비스를 실현하고 새로운 수익 창출의 기회를 가져다 줄 것으로 기대된다. 본고에서는 스몰셀의 개념 및 관련 현황을 개략적으로 살펴보고, 국내외 스몰셀 업계 동향 및 시장전망을 분석하여 시사점을 제시하고자 한다.

• Proceedings of the Korea Society for Industrial Systems Conference
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• 1998.10a
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• pp.645-654
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• 1998

본 연구에서는 인터넷 가상상점의 사용성을 평가하기 위하여 국내에서 성업중인 2개의 대형서점을 선정하여 이들 상점에 대한 사용성을 비교·분석하였다. 사용성 분석 방법으로는 인지과학분야에서 개발된 GOMS를 채택하였으며, 2개의 상점을 비교 분석한 결과 , 다음과 같은 사용성 상의 문제점을 발견하였다. : (1) 상품검색에 꼭 필요하지 않은 정보의 입력과정이 포함되어있지않다. (2) 상품검색을 위한 디렉토리 구조 설계시 깊이와 넓이 사이의 적절한 균형이 유지되어 있지 않다. (3) 서버 접속 회수가 지나치게 많아 구매에 소요되는 시간이 길다. 이상과 같은 사용성의 저하요인은 개발자가 구매자의 사용성을 상대적으로 등한시하고, 검색 효율성과 개발 용이성만을 중시한 결과로 판단되었다. 따라서 개발자는 사용자입장에서 사용 편이성을 고려한 구매절차를 개발하여 이를 가상 상점에 도입하는 것이 필요하다.

• Proceedings of the Korean Information Science Society Conference
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• 2000.10c
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• pp.207-209
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• 2000

인터넷전화 서비스는 저렴한 가격과, 타 서비스와 통합 및 가치부가(Value Added)면에서 기존의 전화에 비해 많은 장점을 가지고 있으나, 상대적으로 낮은 음질로 인하여 사용자의 요구를 만족시키지 못하고 있다. 이것은 현재 인터넷은 best-effort형 패킷 전달 서비스만을 제공하고 있기 때문에 전송지연, 패킷손실, 지터등을 보장할 수 있는 방법이 없기 때문이다. 본 논문에서는 인터넷전화에서 패킷손실이나 전송지연으로 인한 음질 저하문제를 SOLA 알고리즘을 이용해 보완하였다. 제시된 알고리즘에서는 송신측에서 패킷을 전송하면 수신측에서는 수신 패킷에 SOLA 알고리즘을 적용하여 수신 패킷을 사람이 인지하지 못하는 수준에서 확장하여 전송지연으로 인한 패킷손실을 감소시킨다. 시뮬레이션 결과 전송지연으로 인한 패킷 손실 확률이 상당히 감소되었고 음질 또한 상당히 개선되었다.