• Journal of KIISE:Software and Applications
• /
• v.30 no.1_2
• /
• pp.31-39
• /
• 2003

It is often assumed that text regions in images are characterized by some distinctive or characteristic spatial frequencies. This feature is highly intuitive, and thus appealing as much. We propose a method of detecting horizontal texts in natural scene images. It is based on the use of two features that can be employed separately or in succession: the frequency of edge pixels across vertical and horizontal scan lines, and the fundamental frequency in the Fourier domain. We confirmed that the frequency features are language independent. Also addressed is the detection of quadrilaterals or approximate rectangles using Hough transform. Since texts that is meaningful to many viewers usually appear within rectangles with colors in high contrast to the background. Hence it is natural to assume the detection rectangles may be helpful for locating desired texts correctly in natural outdoor scene images.

• Journal of KIISE:Computer Systems and Theory
• /
• v.26 no.9
• /
• pp.1166-1176
• /
• 1999

연속 매체, 특히 비디오 데이타에 대한 일반 사용자 연산에는 재생뿐만 아니라 임의 속도 탐색 연산, 정지 연산, 그리고 그 외 다양한 연산이 있다. 이 연산 중에서 원하는 화면을 빨리 찾는 데에 유용한 고속 전진(FF: fast-forward)과 고속 후진(FB: fast-backward)은 재생 연산과는 달리 비순차적인 디스크 접근을 요구한다. 이러한 경우에 디스크 부하가 균등하지 않으면 일부 디스크에 접근이 편중되어 서비스 품질이 떨어진다. 본 논문에서는 디스크 배열을 이용한 저장 시스템에서 디스크 접근을 고르게 분산시키기 위하여 '소수 라운드 로빈(PRR: Prime Round Robin)' 방식으로 연속 매체를 디스크에 배치하는 기법에서 문제가 됐던 낭비된 디스크 저장 공간을 신뢰도 향상을 위해서 사용하는 '그룹화된 패리티를 갖는 소수 라운드 로빈(PRRgp: PRR with Grouped Parities)' 방식을 제안한다. 이 기법은 PRR 기법처럼 임의 속도 검색 연산에 있어서 디스크 배열을 구성하는 모든 디스크의 부하를 균등하게 할뿐만 아니라 낭비됐던 디스크 저장 공간에 신뢰도를 높이기 위한 패리티 정보를 저장함으로서 신뢰도를 향상시킬 수 있다. 신뢰도 모델링 방법으로 조합 모델과 마르코프 모델을 이용해서 결함발생율과 결함복구율을 고려한 신뢰도를 산출하고 비교.분석한다. PRR 기법으로 연속 매체를 저장하고 낭비되는 공간에 패리티 정보를 저장할 경우에 동시에 두 개 이상의 결함 발생 시에 그 결함으로부터 복구가 불가능하지만 PRRgp 기법에서는 약 30% 이상의경우에 대해서 동시에 두 개의 결함 발생 시에 저장한 패리티 정보를 이용한 복구가 가능할 뿐만 아니라 패리티 그룹의 수가 두 개 이상인 경우에는 두 개 이상의 결함에 대해서도 복구가 가능하다.Abstract End-user operations on continuous media (say video data) consist of arbitrary-rate search, pause, and others as well as normal-rate play. FF(fast-forward) / FB(fast-backward) among those operations are desirable to find out the scene of interest but they require non-sequential access of disks. When accesses are clustered to several disks without considering load balance, high quality services in playback may not be available. In this paper, we propose a new disk placement scheme, called PRRgp(Prime Round Robin with Grouped Parities), with enhanced reliability by using the wasted disk storage space in an old one(PRR: Prime Round Robin), in which continuous media are placed on a disk array based storage systems to distribute disk accesses uniformly. The PRRgp can not only achieve load balance of disks consisting of a disk array under arbitrary-rate search like PRR, but also improve reliability by storing parity information on the wasted disk space appropriately. We use combinatorial and Markov models to evaluate the reliability for a disk array and to analyze the results. When continuous media like PRR are placed and parity information on the wasted disk space is stored, we cannot tolerate more than two simultaneous faults. But they can be recovered by using stored parity information for about 30 percent as a whole in case of PRRgp presented in this paper. In addition, more than two faults can be tolerated in case there are more than two parity groups.

• Proceedings of the Korean Information Science Society Conference
• /
• 2001.10a
• /
• pp.190-192
• /
• 2001

시간에 따라 공간적 위치가 연속적으로 변하는 객체를 이동객체라 한다. 이동객체에 대한 최근접 질의는 시간에 따라 거리도 달라지게 됨으로써 기존의 방법을 그대로 이용하기 어렵다. 본 논문에서는 이동객체에 대한 최근접 질의를 3D R-tree를 이용한 최근접 탐색방법에 시간적 요소를 추가하여 처리하였다. 또, 3D R-tree를 구성하는 노드의 크기에 따른 사장공간(Dead Space)이 최근접 질의에 미치는 영향을 분석하였다. 실험결과에 따르면 이동객체를 하나의 노드에 저장하면 사장공간이 증가하여 불필요한 노드를 접근함으로써 성능이 떨어지고 여러 개로 분할하여 저장하게 되면 색인의 크기가 커짐으로써 질의 처리 성능이 떨어지게 된다. 따라서, 이동객체에 대한 적절한 분할 및 병합 정책이 필요하다는 것을 알 수 있다.

• The KIPS Transactions:PartB
• /
• v.12B no.4 s.100
• /
• pp.429-436
• /
• 2005

A simple stereo matching algorithm using population-based incremental learning(PBIL) is proposed in this paper to decrease the general problem of genetic algorithms, such as memory consumption and inefficiency of search. PBIL is a variation of genetic algorithms using stochastic search and competitive teaming based on a probability vector. The structure of PBIL is simpler than that of other genetic algorithm families, such as serial and parallel ones, due to the use of a probability vector. The PBIL strategy is simplified and adapted for stereo matching circumstances. Thus, gene pool, chromosome crossover, and gene mutation we removed, while the evolution rule, that fitter chromosomes should have higher survival probabilities, is preserved. As a result, memory space is decreased, matching rules are simplified and computation cost is reduced. In addition, a scheme controlling the distance of neighbors for disparity smoothness is inserted to obtain a wide-area consistency of disparities, like a result of coarse-to-fine matchers. Because of this scheme, the proposed algorithm can produce a stable disparity map with a small fixed-size window. Finally, an alterative version of the proposed algorithm without using probability vector is also presented for simpler set-ups.

• Journal of the Korea Society for Simulation
• /
• v.28 no.1
• /
• pp.23-39
• /
• 2019

The use of drone-bots is demanded in times regarding the reduction of military force, the spread of the life-oriented thought, and the use of innovative technology in the defense through the fourth industrial revolution. Especially, the drone's surveillance and reconnaissance are expected to play a big role in the future battlefield. However, there are not many cases in which the concept of operation is studied scientifically. In this study, We propose search algorithms for reconnaissance drone through simulation analysis. In the simulation, the drone and target move linearly in continuous space, and the target is moving adopting the Random-walk concept to reflect the uncertainty of the battlefield. The research investigates the effectiveness of existing search methods such as Parallel and Spiral Search. We analyze the probabilistic analysis for detector radius and the speed on the detection probability. In particular, the new detection algorithms those can be used when an enemy moves toward a specific goal, PS (Probability Search) and HS (Hamiltonian Search), are introduced. The results of this study will have applicability on planning the path for the reconnaissance operations using drone-bots.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.18 no.1
• /
• pp.85-94
• /
• 2017

This study researched the meaning of the outdoor play spaces used by young children, as perceived by them and their teachers. For this purpose, indirect observation, nonformal interviews during the activity of young children and in-depth interviews with teachers were conducted in 3 kindergartens and 1 day care center which operate various programs. As a result, outdoor play spaces were recognized as a psychological space, expanded space and sequential space for the relationships of young children. Meanwhile, early childhood teachers perceived them as a functional space, expanded space and restricted space of the children's daily lives. It was recognized that outdoor play spaces provided the children with good and unstructured environments to reorganize their own daily pattern through expanded play and the chance to naturally form peer relationships. This suggests that the space configuration which is most suitable for child centered development is one that is formed within and by their daily lives, rather than the standardized configuration of outdoor play spaces.

• Journal of the Korean Institute of Telematics and Electronics B
• /
• v.31B no.11
• /
• pp.63-77
• /
• 1994

This paper describes the real-time system which, through analyzing a sequence of images, can extract motional information on a moving object and can contol servo equipment to always locate the moving object at the center of an image frame. An image is a vast amount of two-dimensional signal, so it takes a lot of time to analyze the whole quantity of a given image. Especially, the time needed to load pixels from a memory to processor increase exponentially as the size of an image increases. To solve such a problem and track a moving object in real-time, this paper addresses how to selectively search the spatial and time domain. Based on the selective search of spatial and time domain, this paper suggests various types of techniques which are essential in implementing a real-time tracking system. That is, this paper describes how to detect an entrance of a moving object in the field of view of a camera and the direction of the entrance, how to determine the time interval of adjacent images, how to determine nonstationary areas formed by a moving object and calculated velocity and position information of a moving object based on the determined areas, how to control servo equipment to locate the moving object at the center of an image frame, and how to properly adjust time interval(${\Delta}$t) to track an object taking variable speed.

• Journal of Energy Engineering
• /
• v.12 no.1
• /
• pp.42-48
• /
• 2003

In system planing and operation, voltage and reactive power control is very important. The voltage deviation and system losses can be reduced through control of reactive power sources. In general, there are several different reactive power sources, we used switched shunt capacitor to improve the voltage profile and to reduce system losses. Since there are many switched shunt capacitors in power system, so it if necessary to coordinate these switched shunt capacitors. In this study, Genetic Algorithm (GA) is used to find optimal coordination of switched shunt capacitors in a local area of power system. In case study, the effectiveness of the proposed method is demonstrated in KEPCO's power system. The simulation is performed by PSS/E and the results of simulation are compared with sensitivity method.

• Journal of KIISE:Databases
• /
• v.28 no.3
• /
• pp.344-356
• /
• 2001

This paper deals with the subsequence searching problem under time-warping in sequence databases. Our work is motivated by the observation that subsequence searches slow down quadratically as the average length of data sequences increases. To resolve this problem, the Segment-Based Approach for Subsequence Searches (SBSS) is proposed. The SBASS divides data and query sequences into a series of segments, and retrieves all data subsequences that satisfy the two conditions: (1) the number of segments is the same as the number of segments in a query sequence, and (2) the distance of every segment pair is less than or equal to a tolerance. Our segmentation scheme allows segments to have different lengths; thus we employ the time warping distance as a similarity measure for each segment pair. For efficient retrieval of similar subsequences, we extract feature vectors from all data segments exploiting their monotonically changing properties, and build a spatial index using feature vectors. Using this index, queries are processed with the four steps: (1) R-tree filtering, (2) feature filtering, (3) successor filtering, and (4) post-processing. The effectiveness of our approach is verified through extensive experiments.

• Journal of Korea Multimedia Society
• /
• v.10 no.11
• /
• pp.1367-1383
• /
• 2007

A sensor network consists of a network of sensors that can perform computation and also communicate with each other through wireless communication. Some important characteristics of sensor networks are that the network should be self administered and the power efficiency should be greatly considered due to the fact that it uses battery power. In sensor networks, when large amounts of various stream data is produced and multiple queries need to be processed simultaneously, the power efficiency should be maximized. This work proposes a technique to create an index on multiple monitoring queries so that the multi-query processing performance could be increased and the memory and power could be efficiently used. The proposed SMILE tree modifies and combines the ideas of spatial indexing techniques such as k-d trees and R+-trees. The k-d tree can divide the dimensions at each level, while the R+-tree improves the R-tree by dividing the space into a hierarchical manner and reduces the overlapping areas. By applying the SMILE tree on multiple queries and using it on stream data in sensor networks, the response time for finding an indexed query takes in some cases 50% of the time taken for a linear search to find the query.