• Proceedings of the Korea Information Processing Society Conference
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• 2007.05a
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• pp.818-821
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• 2007

무선 센서 네트워크에서 특정 지역에 분포된 센서들은 데이터를 감지하고, 싱크 노드는 소스 노드들에게서 데이터를 수집한다. 현재, 여러 연구기관 및 기업에서 무선 센서 네트워크를 구현하고 실용화하기 위해 연구하는 중이며, 대표적인 예로 IEEE Standards의 IEEE 802.15.4와 이를 하위 계층으로 사용하는 ZigBee Alliance 의 ZigBee 가 있다. 본 논문에서는, ZigBee 기반의 네트워크에서 감지된 데이터들을 수집하기 위한 이동성을 지원하는 게이트웨이의 정보처리 메커니즘을 설계한다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2021.10a
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• pp.541-542
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• 2021

In this paper, we consider the straggled network treatment in multiple sensor groups. During the moving or the implement of mission, the departed network should be handled. The loss of network group affects the mission implement of overall sensor networks, and it also requests the immediate treatment. In urgent mission environments, the network management of mobile sink should be considered to the group damage.

• Proceedings of the Korean Information Science Society Conference
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• 2012.06a
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• pp.77-79
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• 2012

MSN 라우팅 프로토콜 설계에서 노드의 이동성 정도를 반영하는 것은 중요한 문제이며 다른 네트워크 인자의 특성들과 통합적으로 고려되어야 한다. 하지만, 기존 라우팅 기법들은 이동성의 고려가 미미하거나 다른 환경 인자들과 통합적인 고려가 되지 않았다. 본 논문에서는 모바일 센서 네트워크(MSN)에서 신뢰성 있고 에너지 효율적인 라우팅 기법을 제안한다. 먼저 동적인 네트워크 환경에서 이동성과 패킷발생율에 따른 에너지 소모 패턴 분석을 하였다. 분석된 결과를 바탕으로 제안 기법은 다양한 환경 인자에 따라 에이전트들이 싱크를 중심으로 자율적으로 구성하고 통신한다. 이러한 에이전트 기반의 라우팅 기법은 신뢰성 있고, 에너지 효율적인 통신을 가능하게 한다. 시뮬레이션 결과 제안 기법은 기존 기법에 비해 노드의 이동성의 변화가 심한 환경에서 에너지 효율적임을 보인다.

• Journal of Korea Multimedia Society
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• v.10 no.10
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• pp.1347-1355
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• 2007

A sensor network is composed of a large number of tiny devices, scattered and deployed in a specified regions. Each sensing device has processing and wireless communication capabilities, which enable it to gather information from the sensing area and to transfer report messages to a base station. The energy-efficient routing paths are established when the base station requests a query, since each node has several characteristics such as low-power, constrained energy, and limited capacity. The established paths are recovered while minimizing the total transmit energy and maximizing the network lifetime when the paths are broken. In this paper, we propose a routing algorithm that each sensor node reports its adjacent link information to the sink node when a sink node broadcasts a query. The sink node manages the total topology and establishes routing paths. This algorithm has a benefit to find an alternative path by reducing the negotiating messages for establishing paths when the established paths are broken. To reduce the overhead of collection information, each node has a link information before reporting to the sink. Because the node recognizes which nodes are adjacent. The proposed algorithm reduces the number of required messages, because sensor nodes receive and report routing messages for establishment at the beginning of configuring routing paths, since each node keeps topology information to establish a routing path, which is useful to report sensing tasks in monitoring environments.

• The Journal of the Convergence on Culture Technology
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• v.9 no.4
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• pp.587-592
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• 2023

Plant growth is regulated by a variety of factors, including organic matter availability. Organic nutrients are carbohydrate molecules from photosynthetic products produced by tissues associated with carbon and energy fixation called "sources". These compounds flow through plant vascular bundles into non-photosynthetic or growing tissues called "sinks". Among these possible compounds, the disaccharide fructosyl glucose, sucrose, is the most representative. During the transport of sucrose, the pathway from the source to the sinks can include hydrolysis of sucrose into glucose and fructose derivatives or direct transfer of sucrose. Among the enzymes involved in this, β-D-fructofuranosidase is the most important. Soluble neutral β-D-fructofuranosidase, one of several isoenzymes, is located in intracellular protoplasts and helps plant cells metabolize sucrose to produce energy. In order to track the activity of this enzyme during the course of plant growth, histological methods were used for the most effective immunolocalization. As a result, the activity was higher in the phloem and epidermis than in the mesophyll tissue in the leaf. In the growing stem, activity was high in the phloem, epidermis, and cortex. The activity of the root, which is a sink tissue, was high in all parts, but especially the highest in the root tip part. It is thought that this is because it helps unloading of sucrose in sink tissues that require sucrose degradation and plays a role in hydrolysising sucrose.

• Proceedings of the KIEE Conference
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• 2008.10b
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• pp.534-535
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• 2008

최근 유비쿼터스 기술이 급속도로 발전함에 따라 많은 application들이 다양한 환경에서 통신서비스를 요구하고 있다. 이를 지원하기 위하여 많은 무선 센서 네트워킹 기술들이 제안되었지만 제한된 대역쪽과 높은 에러율로 인하여 이동성을 지원하기에는 부족하였다. 특히, 경로를 획득하기 위한 Route Request (RREQ)의 잦은 브로드캐스트 과정은 오히려 혼잡 및 에너지 소모를 야기시키며 네트워크 성능을 저하시키는 문제점이 있다. 본 논문에서는 언제, 어디서나 다양한 토폴로지 환경에서 자가 구성이 가능하며, 이동성을 지원하는 Tree기반의 Self-Routing 기법을 제안한다. 기존의 센서 네트워크내 멀티홉 라우팅 프로토콜과는 달리, 라우터 혹은 싱크노드의 비컨 프레임내 Association 정보만을 이용하여 새로운 라우팅 테이블을 형성함으로써 컨트롤 패킷의 오버 헤드를 크게 줄일 수 있다. 성능 평가를 위하여 실제 모바일 로봇을 이용한 실험과 시뮬레이션을 동시에 하였으며, 기존의 기법보다 향상된 성능을 가짐을 보인다.

• Smart Media Journal
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• v.5 no.1
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• pp.55-60
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• 2016

Mobility of the sensor networks proposed a new way to the efficient design of sensor networks and improvement of network system performance. Mobility results in a number of functional changes in the MAC protocol and routing protocol. Especially, the mobility of the nodes may occur the increase of the overhead of transmission or disconnection of the link. Therefore, the study of the energy efficient transmission is very important in mobile sensor networks. This paper proposed adaptive transmission mechanism on the distance-based power control. The proposed mechanism was analyzed better than conventional method in the average energy consumption and network life by simulation results.

• Horticultural Science & Technology
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• v.19 no.4
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• pp.555-559
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• 2001

This research was conducted to estimate the chlorophyll contents of chrysanthemum leaves using SPAD-502 chlorophyll meter under different photoperiod and light intensity. Measurements were done at every third leaf intervals starting from the top of the stem to the bottom at harvest time. SPAD value was highest at 10 hours of photoperiods, followed by 13 and 16 hours of photoperiods. In particular, under short day condition, SPAD value was highest in the young leaves below the flower bud and decreased down the leaf profile. Under long day condition, SPAD value reached maximum at leaves between $15-27^{th}$ from the top and decreased to the minimum immediately below the flower bud (youngest leaf). These results may indicate that the younger leaves become strong source of supporting flowers in reproductive stage, while the younger leaves serve as sinks and older leaves support their development in vegetative stage. Changes of SPAD value at different levels of irradiance showed that highest SPAD value were observed at high irradiance and decreased with decreasing irradiance.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2016.05a
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• pp.645-648
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• 2016

Cluster based wireless sensor networks have a characteristic that the cluster heads collect and aggregate data from sensor nodes and send data to sink node. In addition, between the adjacent sensor nodes deployed in the same area is characterized to the similar sensing data. In this paper, we propose a transmission algorithm for improving the energy efficiency using these two features in the cluster-based wireless sensor networks. Adjacent neighboring nodes form a pair and the two nodes sense data on shifts for one round. Additionally, two cluster heads are selected in a cluster and one of them alternately collects data from nodes and transmits data to the sink. This paper describes a transmission rounding method and a transmission frame for increasing energy efficiency and compared with conventional methods. We perform computer simulations to evaluate the performance of the proposed algorithm, and show better performance in terms of energy efficiency as compared with the LEACH algorithm.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 1999.11b
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• pp.239-242
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• 1999

본 논문에서는 8VSB수신기가 다중경로신호에 따른 성능이 나쁜 것에 대한 원인 분석과 나아가 개선책을 제시하기 위해 다중경로 신호가 디지털 지상파 TV의 수신성능에 미치는 영향에 대해 수신단의 STR(Symbol Timing Recovery)과 등화기를 중심으로 분석한다. 첫째 등화기의 성능 분석을 위해 에코의지연시간이 7.5 $\mu$sec일 때 시불변 환경에서 전산 모의 실험을 하였다. 등화기 수렴후의 에로 레벨에 따른 TOV(Threshold of Visibility) S/N(Signal to Noise)를 구해보면 호주의 실험실 측정과는 달리 0dB에서도 S/N이 26dB 정도이면 등화기는 안정적으로 수렴한다. 둘째 세그먼트 동기 복원을 세그먼트 싱크 필터(Segment Sync:+1, +1. -1, -1)를 사용했을 때 짧은 시간 지연 에코와 긴 시간 지연 에코에 대해 S 커브를 보면 짧은 시간 지연에코에서는 심볼 타이밍이 어긋났으며 긴 시간 지연 에로에서는 문제가 없이 타이밍 동기가 된다. 셋째 짧은 시간 지연 에코신호가 있을 때 세그먼트 동기 복원과 등화기를 연동한 전산 모의 실험을 하여 에코의 영향을 분석하고 FSE(Fractionally Spaced Equalizer) 등화기 사용에 따른 장점을 분석한다.