• Applied Biological Chemistry
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• v.41 no.7
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• pp.533-538
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• 1998

In order to gain fundamental information on the utilization of lipids as energy source in mud-skipper, muscle lipids and their fatty acid composition were investigated with respect to life cycle-maturation (Aug), before-hibernation (Nov), and after-hibernation (Apr). Crude and neutral lipid were found to decrease from 1.2, 68.3% (Aug) via 0.7, 53.8% (Nov) to 0.4, 42.6% (Apr), respectively, whilst phospholipids and glycolipids increased from 29.5 and 2.2% (Aug) to 52.1 and 5.3% (Apr), respectively. In neutral lipids, TG contents gradually decreased from 53.8% (Aug) via 33.6% (Nov) to 23.1% (Apr), while FFA and sterol contents increased from 13.5 and 14.2% (Aug) to 22.3 and 24.5% (Apr), respectively. In phospholipids, PC content decreased from 61.2% (Aug) to 50.6% (Apr), while changes in PS and PE contents, as a whole, showed the opposite trends. In neutral lipids, the levels of some fatty acids such as 16:0, 16:1, 18:0, 18:1 and 20:5 $({\omega}3)$ were analyzed to be high, with the 20 : 5 being predominant, and the levels of saturated and monoene-acids gradually decreased, while polyene-acids increased in before and after hibernation. In before hibernation, 16:0, 16:1, 18:1 mainly decreased but 18:2, 18:3 $({\omega}3)$ and most of saturated and monoene acids such as 14:0, 14:1, 16:1, 18:0, 18:1 slightly decreased in after hibernation. From these findings, it was suggested that those fatty acids decreased during hibernation were used as a energy source, particularly 16:1 and 18:1 being most preferentially used. In phospholipids, the levels of 16:0, 18:0, 20:5 $({\omega}3)$, 22:5 $({\omega}3)$ and 22:6 $({\omega}3)$ were found to be high. Throughout the life cycle, the levels of monoene-acids in phospholipids stayed constant, whilst those of 18:2, 18:3 $({\omega}3)$ and saturated acids such as 16:0, 18:0 were found to be decreased gradually in before and after hibernation, whereas those for the high degree of polyene-acids such as 20:4 $({\omega}6)$, 20:5 $({\omega}3)$, 22:5 $({\omega}3)$, 22:6 $({\omega}3)$ increased, particularly 20:4 $({\omega}6)$, 20:5 $({\omega}3)$ being most increased.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.13 no.1
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• pp.115-120
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• 2013

There are lots of vulnerability and chance to be attacked in wireless sensor networks, which has many applications. Among those attacks, sybil attack is to generate a lot of false node and to inject false information into networks. When a user uses such false information without recognizing the attack, there might be a disaster. Although authentication method can be used to protect such attack, the method is not a good choice in wireless sensor networks, where sensor nodes have a limited battery and low power. In this paper, we propose a novel method to detect sybil attack with a little extra overhead. The proposed method use the characteristics that there is a weak connection between a group of normal nodes and a group of false nodes. In addition, the method uses energy aware routing based on random routing and adds a little information into the routing. Experimental results show that the proposed method detects false node by more than 90% probability with a little energy overhead.

• Journal of Satellite, Information and Communications
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• v.11 no.3
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• pp.119-122
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• 2016

Feature detection is recognized as an accurate spectrum sensing approach when the information of the desired signal is partly known at the receiver. This type of detection was proposed to overcome large noise environment. Cyclostationary detection is an example of feature detection in spectrum sensing technique in cognitive radio. However, the cyclostationary process calculation requires a lot of processing time and information about the designed signals. On the other hand, energy detection spectrum sensing is widely known as a simple and compact spectrum sensing technique. However, energy detection is highly affected by large noise and lead to high detection error probability. In this paper, the combination of energy detection and cyclostationary is proposed in order to increase the accuracy and decrease the calculation and processing time. The two-layer threshold is utilized in order to reduce the complexity of computation and processing time in cyclostationary which can lead to the improved throughput of the system. The simulation result shows that the implementation of energy-based cyclostationary detector can help to improve the performance of the system while it can considerably reduce the required time for signal detection.

• Journal of the Korean Society of Food Science and Nutrition
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• v.43 no.6
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• pp.916-925
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• 2014

The purpose of this study was to compare dietary and lifestyle habits in middle-aged women based on their self-perceived health-related physical fitness (SPF) level as well as investigate the effects of dietary and lifestyle habits on SPF. The study subjects were divided into two groups, 'High' group (${\geq}3.2$, n=64) and 'Low' group (<3.2, n=69), based on average SPF value (3.2). Women in the 'High' group showed a greater lean mass (P<0.05), whereas women in the 'Low' group had higher triglycerides (P<0.05). In analyzing characteristics of lifestyle habits, it was found that the 'High' group showed significantly higher scores for 'vitality level (P<0.001)', 'self-rated health status (P<0.001)', 'regular medical checkups (P<0.05)', and 'regular exercise (P<0.05)'. The average score for dietary habits was significantly high in the 'High' group (P<0.05). Furthermore, ordinary dietary habits showed a significant positive correlation (P<0.001) with SPF in the regression analysis after adjusting for disturbance factors. From these results, ordinary desirable dietary habits were shown to be an important factors having positive effects SPF. Therefore, healthy dietary and lifestyle habits should be practiced to improve the SPF of middle-aged women. For this purpose, related educational programs should be developed for the middle-aged women to take interest in their dietary habits.

• Information and Communications Magazine
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• v.26 no.1
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• pp.25-30
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• 2009

IT산업은 '97년 외환위기를 기점으로 고성장을 거듭하였고, 세계 10위권 규모의 경제 강국으로 성장하는데 있어 국내 산업의 대표적인 성장동력으로서 자리 매김하였다. 하지만, 최근 성장률이 예전만 못하다는 우려의 목소리와 함께 IT가 한 단계 더 업그레이드하기 위해서는 자신의 허물을 과감히 벗는 용기가 필요하다는 것이 일반적인 시각이다. 이러한 흐름속에서 기존 IT전략과 차별화된 New IT 발전방안을 수립하게 되었다. 지금까지의 IT전략이 IT 고도화 추진을 위한 IT 중심 발전 전략이었다면, New IT전략은 IT기반 융합산업, IT융합 신산업, Next IT산업 등3대 성장축간 시너지 창출이 가능한 IT로의 수렴과 확산이 핵심이라고 할 수 있다. IT기반 융합산업의 최종 목표는 전통산업과 IT가 만나 자동차, 조선, 의료, 국방, 건설, 섬유, 기계항공 등 7개 주력기간산업의 고부가가치화 및 초일류화를 우선 실현하는 것이다. IT융합 신산업의 최종 목표는 나노(NT), 바이오(BT), 인지기술(CT) 등 비(非)IT와 교감을 통하여 IT가 에너지, 환경, 건강 등 사회적 문제를 해결하고, 녹색성장 추진의 핵심인 5대 신산업을 창출하는데 있다. 5대 신산업으로는 Green IT산업, Welfare-Infra산업, 감성조명산업, 인지단말산업, THz응용산업 등을 꼽을 수 있다. Next IT산업은 기존 14대 IT 분야를 'ETRI 비전 2020' 등 미래 청사진을 바탕으로 장기적 관점에서 재설계한 것이며, 최종 목표는 TDX, 4M D램, CDMA, 와이브로, DMB, NoLA 등 IT 강국 계보를 이어갈 4G, 미래인터넷, Smart Radio, 실감미디어, 웹3.0, 투명전자소자 등 미래 유망 핵심원천기술을 확보하고, IT 경쟁력을 강화하는 것이다.

• Proceedings of the Korean Information Science Society Conference
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• 2011.06a
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• pp.381-384
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• 2011

최근 무선 센서 네트워크의 수집 데이터에 대해 에너지 효율적인 저장 및 질의 처리를 위한 다양한 연구가 이루어지고 있다. 데이터 중심 저장 (DCS: Data-Centric Storage) 기법은 인-네트워크 방식 기반의 효율적인 데이터 저장과 질의 처리를 위해 제안된 기법이다. DCS 기법은 수집 데이터의 값에 따라 저장 될 위치를 미리 결정하여 각 데이터가 발생시 해당 위치에 인-네트워크 방식으로 저장한다. 이를 통해 질의 처리시 불필요한 질의 배포를 최소화 시킨다. 하지만 기존에 제안된 DCS 기법들은 수집되는 데이터의 발생 범위를 고정적으로 설정한다. 따라서 시기별로 상이한 범위의 데이터가 발생되는 실제 응용에 서는 저장 공간 활용의 불균등을 초래하여 네트워크 수명을 단축시킨다. 본 논문은 시간이 지남에 따라 변화 하는 데이터 발생 패턴에 상황 적응적인 범위 설정 기법을 적용하여 네트워크 전반에 걸쳐 노드들의 저장 공간을 균등하게 사용하는 상황 인지 데이터 중심 저장 방식을 제안한다. 또한 제안하는 기법의 우수성을 보이기 위해 기존 DCS 기법과 성능을 비교평가 한다.

• Journal of Satellite, Information and Communications
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• v.11 no.4
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• pp.52-57
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• 2016

The backscatter signals are very weak so they can be easily interfered by signal interferences and channels. In this paper, we propose a two-level classification algorithm for backscatter communications which chooses the idle frequency channel based on cognitive radio systems. The two-level classification algorithm provides an optimal idle frequency channel by obtaining informations about idle frequencies, fading of the channels, and the channels' usage state by primary users. Our simulation results show the improvement of BER and received power performance in backscatter communications by using the proposed algorithm, and the improvement of the algorithm's performance in backscatter communications.

• The Journal of the Korea institute of electronic communication sciences
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• v.11 no.2
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• pp.197-202
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• 2016

This study suggests a novel way of safety cognition with single sensor. It is beneficial to make the most of the 3-axis acceleration sensor for context inference. It has remarkable advantages that size is too small and less malfunction or error. This study shows the calculation of the common life safety through the events data from the 3-axis acceleration sensor only. That includes the analyzation of the volume of energy and converting quantitative numerical value.

• Journal of the Korean Institute of Intelligent Systems
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• v.22 no.2
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• pp.148-153
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• 2012

In this paper, we propose a fault-tolerant QoS routing scheme based on interference awareness for providing both high throughput and minimum end-to-end delay for wireless sensor networks. With the proposed algorithm, it is feasible to find out the optimal transmission path between sensor nodes to the sink node by using cumulative path metric where real-time delivery, high energy efficiency and less interference are considered as in path selection. Finally, simulation results show that network throughput and delay can be improved by using the proposed routing scheme.

• Journal of Satellite, Information and Communications
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• v.9 no.4
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• pp.20-25
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• 2014

In this paper, we provide efficient spectrum sensing technology for smooth use of frequency and energy charge of multi-copter. The proposed structures focus on improving performance of spectrum sensing that is based on Ad-hoc network. First, we explain basic principles and disadvantages of cooperative spectrum sensing and ad-hoc based spectrum sensing. To solve these problems, in this paper, we employ the beamforming technology that guarantees higher transmit primary users' signal power to secondary users in ad-hoc network. The performance of proposed algorithm is analyzed in terms of detection probabilities, and the results of this paper can be applied to the various ad-hoc based Cognitive Radio system.