• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2012.10a
• /
• pp.1003-1006
• /
• 2012

The image correction algorithm and system design for CMOS sensor to enhance the image resolution is presented in this paper. The proposed algorithm finds out the image cell from the sensor and process them by the limited memory configuration. The evaluation of the method is done by the designed hardware system. The experimental results are capable of improving contrast per channel and of sensing equalized image quality on an edge of image.

• Journal of KIISE:Databases
• /
• v.35 no.1
• /
• pp.84-95
• /
• 2008

Wireless sensor networks have recently emerged as a platform for several applications. By deploying wireless sensor nodes and constructing a sensor network, we can remotely obtain information about the behavior, conditions, and positions of objects in a region. Since sensor nodes operate on batteries, energy-efficient mechanisms for gathering sensor data are indispensable to prolong the lifetime of a sensor network as long as possible. In this paper, we propose a novel clustering algorithm that distributes the energy consumption of a cluster head. First, we analyze the energy consumption if cluster heads and divide each cluster into a collection layer and a transmission layer according to their roles. Then, we elect a cluster head for each layer to distribute the energy consumption of single cluster head. In order to show the superiority of our clustering algorithm, we compare it with the existing clustering algorithm in terms of the lifetime of the sensor network. As a result, our experimental results show that the proposed clustering algorithm achieves about $10%{\sim}40%$ performance improvements over the existing clustering algorithms.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.31 no.3
• /
• pp.31-38
• /
• 2003

In the present work, a nonlinear inverse perturbation method which has been used in the structural optimization, is adopted so as to identify the structural damages. Unlike the structural optimization, a larger number of constrained equations than the number of unknown parameters are often required detect structural damage. Therefore, nonlinear least squares method is utilized to solve the problem. Because only a limited number of sensors are available I real situation of damage detection, the determination of sensor location becomes one of the most important issues. Hence, this work concentrates on the issue of sensor placement in the framework of nonlinear inverse perturbation method, and the performances of various methodologies concerning to sensor placement are compared with each other. The comparisons show tat the successive elimination method gets good performance for sensor placement. From the several numerical studies, it is confirmed that the inverse perturbation method, combined with the successive elimination method, is very promising in structural damage detection.

• Journal of Digital Convergence
• /
• v.10 no.1
• /
• pp.371-378
• /
• 2012

Through sensor nodes it can obtain behavior, condition, location of objects. Generally speaking, sensor nodes are very limited because they have a battery power supply. Therefore, for collecting sensor data, efficient energy management is necessary in order to prolong the entire network survival. In this paper, we propose a method that increases energy efficiency to be self-configuring by distributed sensor nodes per cluster. The proposed method is based on the ANTCLUST. After measuring the similarity between two objects it is method that determine own cluster. It applies a colonial closure model of ant. The result of an experiment, it showed that the number of alive nodes increased 27% than existing clustering methods.

• Journal of Korean Society for Geospatial Information Science
• /
• v.18 no.2
• /
• pp.3-12
• /
• 2010

In previous studies, the digital measurement systems and analysis algorithms were developed by using the related techniques, such as the aerial photograph detection and high resolution satellite image process. However, these studies were limited in 2-dimensional geo-processing. Therefore, it is necessary to apply the 3-dimensional spatial information and coordinate system for higher accuracy in recognizing and locating of geo-features. The objective of this study was to develop a stochastic algorithm for the optimal sensor placement using the 3-dimensional spatial analysis method. The 3-dimensional information of the LiDAR was applied in the sensor field algorithm based on 2- and/or 3-dimensional gridded points. This study was conducted with three case studies using the optimal sensor placement algorithms; the first case was based on 2-dimensional space without obstacles(2D-non obstacles), the second case was based on 2-dimensional space with obstacles(2D-obstacles), and lastly, the third case was based on 3-dimensional space with obstacles(3D-obstacles). Finally, this study suggested the methodology for the optimal sensor placement - especially, for ground-settled sensors - using the LiDAR data, and it showed the possibility of algorithm application in the information collection using sensors.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.12 no.8
• /
• pp.1505-1510
• /
• 2008

In large-scale wireless sensor networks, the deployed nodes cannot be replaced or recharged after first deployment. Also, dead nodes maγ lead to the partition of whole networks. While performing data dissemination under a battery power constraint, energy efficiency is a key design factor of routing protocol. As a solution for the efficient data dissemination, in this paper, we propose a protocol namely Hierarchical Data Dissemination (HDD) which provides scalable and efficient data delivery to multiple sources and mobile sinks. HDD uses the facts that sink nodes are central gathering Points and source-centric data forwarding paths are constructed and it is maintained with two-tier communications. The performance of HDD is compared with TTDD about the energy consumption, data delivery time and data success ration. The extensive simulation results show that HDD Routing Protocol outperforms TIDD by more than $1.5{\sim}3times$ on energy consumption.

• Journal of Advanced Navigation Technology
• /
• v.14 no.1
• /
• pp.49-56
• /
• 2010

Severe energy constraints and the low power consumption require the significance of the energy efficient error control mechanisms in wireless sensor network (WSN). In this paper, an automatic repeat request (ARQ) methodology for the analysis of error control schemes in WSN is presented such that the effects of packet length, the modulation scheme and the interference effect of the wireless channel are investigated. Moreover, an analyis of ARQ error control is provided by considering two major architectures for wireless sensor network, i.e., Mica2 and MicaZ sensor nodes. And the throughput performance of WSN with asynchronous FSK signal and DSSS-OQPSK signal with selective repeat ARQ scheme are analyzed in multiple interference environment, and the probability of receiving a correct bit and packet from target node to sink node is evaluated as a function of the channel parameter, the number of wireless sensor node, and the spreading factor.

• The Journal of the Acoustical Society of Korea
• /
• v.17 no.4
• /
• pp.42-50
• /
• 1998

본 논문에서는 Gram-Schmidt 구조와 Inverse Power Method를 이용한 고유 부공간 추정 방법을 제안하고 입사각을 추정하는 문제에 적용하여 성능을 평가하였다. 그리고, 어레 이 센서들이 가운데를 중심으로 대칭으로 배열되어 있을 때, 전후방 GS 필터를 이용한 향 상된 고유 부공간 방법을 제안하였다. 그리고, 제안한 방법들을 제한조건을 갖는 gradient search 방법과 비교하였다.

• Information and Communications Magazine
• /
• v.28 no.6
• /
• pp.39-46
• /
• 2011

실감 통신의 구현을 위해서는 의사 소통 상대자가 서로 얼굴을 맞대고 이야기하는 것과 같은 분위기를 통신 단말을 통해 구현이 가능해야 하며, 상대방과의 상호작용도 가능해야 한다. 이러한 통신단말을 구현하기 위한 기본 조건은 연속시차에 기반한 눈에 피로감을 주지 않는 3차원 영상과 이들 영상과 접촉 및 분위기 전달이 가능한 감성 및 오감 수수 기술의 개발에 의해서만 충족된다. 이들 감성 및 오감 수수가 가능하기 위해서는 단말 자체가 디스플레이에 다수의 센서를 융합시킨 다 기능 융합미디어의 역할을 해야 하며 눈에 피로감과 시청자의 자세제한을 요구하지 않는 3차원 영상이 이 디스플레이를 통해 표시되어야한다.

• Journal of KIISE:Databases
• /
• v.36 no.1
• /
• pp.8-21
• /
• 2009

A wireless sensor network is a computer network which consists of spatially distributed devices, called sensor nodes. In wireless sensor networks, energy efficiency is a key issue since sensor nodes must resides upon limited energy. To retrieve sensor information without dealing with the network issues, a sensor network is treated as conceptual database on which query can be requested. When multiple queries are requested for processing in a wireless sensor network, energy consumption can be significantly reduced if common partial results among similar queries can be effectively shared. In this paper, we propose an energy efficient multi-query processing technique based on the coverage relationship between multiple queries. When a new query is requested, our proposed technique derives an equivalent query from queries running at the moment, if it is derivable. Our technique first computes the set of running queries that may derive a partial result of the new query and then test if this set covers all the result of the new query attribute-wise and tuple-wise. If the result of the new query can be derived from the results of executing queries, the new query derives its result at the base station instead of being executed in the sensor network.