• The Journal of the Convergence on Culture Technology
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• v.4 no.4
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• pp.367-372
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• 2018

This paper proposed an algorithm that detects boundary nodes effectively in wireless sensor network. A boundary node is a sensor that lies on the border of network holes or the outer boundary of wireless sensor network. Proposed algorithm detects boundary nodes using only the position information of sensors. In addition, to improve detect performance, sensor computes the overlap area of nearest sensor first. Simulation is performed to validate the process of the proposed algorithm. In Simulation, several obstacles are placed and varying number of sensors in the range of 500~1500 are deployed in the area in order to reflect real world. The simulation results shows that proposed algorithm detects boundary nodes effectively that are located on the border of holes and the outer boundary of wireless sensor network.

• Proceedings of the Korean Information Science Society Conference
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• 2010.06d
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• pp.354-359
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• 2010

센서 네트워크는 광범위한 영역에서 다양한 환경정보를 수집 가능하다. 센서 네트워크 환경에서 발생하는 다양한 이벤트 유형 중에 군집 이벤트는 객체의 군집, 물질의 확산 등과 같은 다양한 형태로 발생한다. 센서의 에너지 제약 특성을 고려하여 군집 이벤트에 대한 에너지 효율적인 탐지 기법에 대한 다양한 기법들이 연구되고 있다. 기존에 제안된 군집 이벤트 탐지 기법들 중 이벤트를 감지한 모든 노드들의 정보를 이용하지 않고, 이벤트의 경계 정보만을 추출하여 기지국으로 전송함으로써 군집 이벤트를 탐지하는 기법이 제안되었다. 하지만 군집 이벤트의 범위가 넓어지고 센서의 배포 밀도가 높을 경우 경계에 위치한 노드들 또한 증가하여 많은 전송 비용을 필요로 한다. 본 논문에서는 에너지 효율적인 군집 이벤트 탐지를 위해 이벤트 경계 노드들의 정보를 압축/요약하여 나타낼 수 있는 인-네트워크 최소 경계 다각형을 생성 기법을 제안한다.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2009.10a
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• pp.7-10
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• 2009

터널 경계구역 내의 필수 조명기준은 가시기준, 즉 충분한 물체의 대비에 의해 결정된다. 본 연구에서는 터널도로를 대상으로 주간의 터널 입구부의 배경을 디지털 카메라로 측정하고, 그 이미지를 감지대비법의 일종인 광막휘도법(Veiling Luminance Method)과 기존 $20^{\circ}$ 시야의 L20법에 적용하여 터널의 경계부 평균휘도를 산출하였으며, 그 결과를 비교, 분석하였다.

• Proceedings of the Korea Information Processing Society Conference
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• 2022.05a
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• pp.88-89
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• 2022

라이다 센서는 최근 다양한 산업에서 3 차원 물체의 식별을 위해 사용되고 있다. 주요 시설이나 전시관의 경계를 위해서 스캔형 라이더는 넓은 범위의 감지를 할 수 있지만 입력 데이터가 많아 물체의 식별과 관련된 연산이 오래 걸리는 문제를 가진다. 이러한 문제를 해결하기 위해서 제안하는 방법에서는 라이다 데이터를 간략화 하고 감지 이벤트를 통해 사용자들에게 알려줄 수 있도록 하는 알고리즘을 제안한다.

• Journal of the Korean Institute of Gas
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• v.20 no.5
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• pp.104-111
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• 2016

Recently, the quantities of chemical material are increasing in chemical industries. At that time, release accident is increasing due to aging of equipment, mechanical failure, human error, etc. and industrial complexes found community properties in a specific area. For that matter, chemical release accident can lead to hight probability of large disaster. There is a need to analyze the boundaries optimal sensor placement calculated by selecting release scenarios through release condition and wether condition in a chemical process for release detection and response. This paper is to investigate chlorine release accident scenarios using COMSOL. Through accident scenarios, a numerical calculation is studied to determine optimized sensor placement with weight of detection probability, detection time and concentration. In addition, validity of sensor placement is improved by robustness analysis about unpredicted accident scenarios. Therefore, this verifies our studies can be effectively applicable on any process. As mention above, the result of this study can help to place mobile sensor, to track gas release based concentration data.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2015.05a
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• pp.93-96
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• 2015

In this paper, we introduce a fire detection system using context-aware sensor. In existing weather and based on vision sensor of fire detection system case, acquired image through sensor of camera is extracting features about fire range as processing to convert HSI(Hue, Saturation, Intensity) model HSI which is color space can have durability in illumination changes. However, in this case, until a fire occurs wide range of sensing a fire in a single camera sensor, it is difficult to detect the occurrence of a fire. Additionally, the fire detection in complex situations as well as difficult to separate continuous boundary is set for the required area is difficult. In this paper, we propose an algorithm for real-time by using a temperature sensor, humidity, Co2, the flame presence information acquired and comparing the data based on multiple conditions, analyze and determine the weighting according to fire it. In addition, it is possible to differential management to intensive fire detection is required zone dividing the state of fire.

• Journal of the Korean Institute of Gas
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• v.21 no.2
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• pp.41-49
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• 2017

Recently, as the number of facilities using chemicals is increasing, the amount of handling is rapidly increasing. However, chemical spills are occurring steadily, and if large quantities of chemicals are leaked in time, they are likely to cause major damage. These industrial complexes use information obtained from a number of sensors to detect and monitor leaking areas, and are used in industrial fields by applying existing fixed sensors to robots and drones. Therefore, it is necessary to propose a sensor placement method at the interface for rapid detection and response based on various leaking scenarios reflecting leaking conditions and environmental conditions of the chemical handling process. In this study, COMSOL was used to analyze the actual accident scenarios by applying the medium parameter to the case of chemical leaks. Based on the accident scenarios, the objective function is selected so that the velocity of each robot is calculated by attaching importance to each item of sensor detection probability, sensing time and sensing scenario number. We also confirmed the feasibility of this method of reliability analysis for unexpected leak accidents. Based on the above results, it is expected that it will be helpful to trace back the leakage source based on the concentration data of the portable sensor to be applied later.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.9 no.5
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• pp.155-161
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• 2009

This paper proposes a high capacity data hiding method using modulus function of pixel-value differencing (PVD) and least significant bit (LSB) replacement method. Many novel data hiding methods based on LSB and PVD methods were presented to enlarge hiding capacity and provide an imperceptible quality. A small difference value for two consecutive pixels is belonged to a smooth area and a large difference one is located on an edge area. In our proposed method, the secret data are hidden on the smooth area by the LSB substitution method and PVD method on the edge area. From the experimental results, the proposed method sustains a higher capacity and still a good quality compared with other LSB and modified PVD methods.

• The Journal of the Korea Contents Association
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• v.10 no.12
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• pp.101-108
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• 2010

Many works on energy-efficient cluster event detection schemes have been done considering the energy restriction of sensor networks. The existing cluster event detection schemes transmit only the boundary information of detected cluster event nodes to the base station. However, If the range of the cluster event is widened and the distribution density of sensor nodes is high, the existing cluster event detection schemes need high transmission costs due to the increase of sensor nodes located in the event boundary. In this paper, we propose an energy-efficient cluster event detection scheme using the minimum boundary polygons (MBP) that can compress and summarize the information of event boundary nodes. The proposed scheme represents the boundary information of cluster events using the MBP creation technique in the large scale of sensor network environments. In order to show the superiority of the proposed scheme, we compare it with the existing scheme through the performance evaluation. Simulation results show that our scheme maintains about 92% accuracy and decreases about 80% in energy consumption to detect the cluster event over the existing schemes on average.

• The Journal of the Acoustical Society of Korea
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• v.19 no.5
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• pp.13-19
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• 2000

The blind segmentation method, which segments input speech data into recognition unit without any prior knowledge, plays an important role in continuous speech recognition system and corpus generation. As no prior knowledge is required, this method is rather simple to implement, but in general, it suffers from bad performance when compared to the knowledge-based segmentation method. In this paper, we introduce a method to improve the performance of a blind segmentation of Korean continuous speech by postprocessing the segment boundaries obtained from the blind segmentation. In the preprocessing stage, the candidate boundaries are extracted by a clustering technique based on the GLR(generalized likelihood ratio) distance measure. In the postprocessing stage, the final phoneme boundaries are selected from the candidates by utilizing a simple a priori knowledge on the syllabic structure of Korean, i.e., the maximum number of phonemes between any consecutive nuclei is limited. The experimental result was rather promising : the proposed method yields 25% reduction of insertion error rate compared that of the blind segmentation alone.