• KIISE Transactions on Computing Practices
• /
• v.22 no.3
• /
• pp.145-150
• /
• 2016

Finding the exact location of faults in a program requires enormous time and effort. Several fault localization methods based on control flows of a program have been studied for decades. Unfortunately, these methods are not applicable to programs based on data-flow languages. A recently proposed mutation-based fault localization method is applicable to data-flow languages, as well as control-flow languages. However, there are no studies on the effectiveness of the mutation-based fault localization method for data-flow based programs. In this paper, we provided an experimental case study to evaluate the effectiveness of mutation-based fault localization on programs implemented in Function Block Diagram (FBD), a widely used data-flow based language in safety-critical systems implementation. We analyzed several real faults in the implementation of FBD programs of a nuclear reactor protection system, and evaluated the mutation-based fault localization effectiveness for each fault.

• Proceedings of the Korean Society of Broadcast Engineers Conference
• /
• 2002.11a
• /
• pp.49-55
• /
• 2002

기존의 영상 획득 시스템들이 어느 정도의 엘리어싱을 허용하도록 제작되어왔음에도 불구하고, 고해상도 영상에 대한 요구는 점점 더 증가하고 있다. 본 논문에서는 부정확한 부화소 단위의 위치추정 오류를 고려한 고해상도 재구성 알고리즘을 제안한다. 부정확한 부화소 위치 추정 오류로 인해 생기는 불량위치문제(ill-posedness)를 해결하기 위해 정규화된 반복 연산법을 적용하였다. 특히 여러장의 저해상도 영상들을 개별적으로 고려하기에 적합한 다중채널 영상 재구성 방법을 도입하였다. 각 저해상도 영상에서 발생하는 움직임 추정오류는 서로 다른 경향성을 나타내므로, 정규화 파라미터들은 각 채널에 맞게 결정되어야 한다. 이를 위채 정규화 파라미터들을 자동으로 결정하는 방법을 제안한다. 제안한 알고리즘은 움직임 추정 오류에 매우 안정하며, 원 영상과 잡음에 대한 사전정보를 필요로 하지 않는다. 또한 주관적인 측면과 객관적인 측면에서 모두 우수한 결과를 실험적으로 보인다.

• Journal of KIISE:Information Networking
• /
• v.36 no.1
• /
• pp.24-33
• /
• 2009

In patch-and-stitch localization algorithms, a flip error refers to the kind of error in which a patch is stitched to the map as being wrongly reflected. In this paper, we present an anchor-free localization algorithm which tries to detect and prevent flip errors. The flip error prevention is achieved by two filtering mechanisms: the flip-ambiguity test and the flip-conflict detection. We evaluate the performances of proposed techniques though simulations and show that they achieve significant performance improvements.

• Proceedings of the Korean Information Science Society Conference
• /
• 2010.06d
• /
• pp.165-169
• /
• 2010

무선 센서 네트워크에서 LBS(Location Based Services) 에 적합한 기술적인 요구사항이 증가하고 있다. 최근 LBS의 가장 기본이 되는 위치추정(Localization) 에 관련하여 많은 알고리즘이 제안되고 있지만 센서 네트워크를 위한 요구사항을 만족하지 못하고 있다. 본 논문에서는 센서 네트워크에서 5가지 주된 위치추정방식의 요구사항을 정의하고 이를 만족하는 SCORE 알고리즘을 제안한다. 고정노드는 다중 파워의 비콘신호를 전승하게 되며, 이때 고정노드는 센서노드에게 위치정보를 비콘 신호에 담아서 전승하게 되는데 이때 다중 비콘신호에 신호 순서에 해당하는 SCORE 라고 고정노드로부터 센서노드까지의 거리에 대한 값을 포함하여서 전승하게 된다. 여러 고정노드로부터 수신한 위치정보를 수집한 센서노드는 간단한 연산과정을 거쳐 자신의 위치를 분산적으로 추정하게 된다. CAB 위치추정 알고리즘의 2 가지 알고리즘을 동시에 사용하는 복잡성 문제와 Diffusion 알고리즘의 네트워크 외곽에서 발생하는 큰 위치추정 오류의 문제점을 SCORE 알고리즘에서는 해결하였다. 시뮬레이션 결과 SCORE 알고리즘은 독립적인 알고리즘 사용임에도 불구하고 CAB 위치추정 알고리즘과 비슷한 성능을 나타내었으며, Diffusion 알고리즘에서 발생한 네트워크 외곽 센서노드들의 오류를 평균 7% 이상 향상 시켰다.

• Journal of Broadcast Engineering
• /
• v.8 no.1
• /
• pp.19-29
• /
• 2003

The demand for high-resolution images is gradually increasing, whereas many imaging systems yield aliased and undersampled images during image acquisition. In this paper, we propose a high-resolution image reconstruction algorithm considering inaccurate subpixel registration. A regularized Iterative reconstruction algorithm is adopted to overcome the ill-posedness problem resulting from inaccurate subpixel registration. In particular, we use multichannel image reconstruction algorithms suitable for application with multiframe environments. Since the registration error in each low-resolution has a different pattern, the regularization parameters are determined adaptively for each channel. We propose a methods for estimating the regularization parameter automatically. The preposed algorithm are robust against the registration error noise. and they do not require any prior information about the original image or the registration error process. Experimental results indicate that the proposed algorithms outperform conventional approaches in terms of both objective measurements and visual evaluation.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.41 no.6
• /
• pp.640-651
• /
• 2016

We propose an effective ToA-based localization method considering accuracy in indoor environments. The purpose of the localization system is to estimate the coordinates of the geographic location of target device. In indoor environments, accurately estimating the location of a target device is not easy due to various errors. The accuracy of wireless localization is influenced by NLOS errors. ToA-based localization measures the location of a target device using the distances between a mobile device and three or more base stations. However, each of the NLOS errors along a distance estimated from a target device to a base station is different because of dissimilar obstacles. To accurately estimate the target's location, an optimized localization process is needed in indoor environments. In this paper, effective ToA-based localization method process is proposed for improving accuracy in wireless sensor networks. Performance evaluations are presented, and the experimental localization system results are proved through comparisons of various localization methods with the proposed methods.

• Proceedings of the IEEK Conference
• /
• 2003.11a
• /
• pp.145-148
• /
• 2003

움직임 벡터의 상관도, 움직임 벡터의 분포특성, 블록 정합 오류의 특성은 탐색 패턴과 탐색 방법을 결정하는 중요한 요소이다. 일반적으로 움직임 벡터는 주로 탐색영역의 가운데를 중심으로 수평 흑은 수직축에 주로 분포한다. 또한 탐색 영역 내의 정합 오류 값의 분포를 보면 움직임 벡터의 분포와 비슷한 형태로 정합 오류의 값들이 수평 혹은 수직 방향으로 최소 정합 오류 값의 위치로 단조 감소해 나간다. 본 논문에서는 이러한 블록 정합 오류의 특성을 이용한 새로운 탐색 방법을 제안하며 주변 블록의 움직임 벡터의 상관도를 이용하여 초기 탐색 지점을 선택하는 고속 움직임 추정 알고리즘을 제안한다. 또한 모의실험을 통하여 기존의 여러 움직임 추정 알고리즘과 비교하여 PSNR 의 감소는 거의 없으면서 매크로블록당 평균 탐색포인트와 수행 시간의 향상을 얻을 수 있음을 확인한다.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.18 no.10
• /
• pp.2562-2570
• /
• 2014

One of the important hints for inferring the function of unknown proteins is the knowledge about protein subcellular localization. Recently, there are considerable researches on the prediction of subcellular localization of proteins which simultaneously exist at multiple subcellular localization. In this paper, label power-set classification is improved for the accurate prediction of multiple subcellular localization. The predicted multi-labels from the label power-set classifier are combined with their prediction probability to give the final result. To find the accurate probability estimates of multi-classes, this paper employs pair-wise comparison and error-correcting output codes frameworks. Prediction experiments on protein subcellular localization show significant performance improvement.

• Journal of the Institute of Electronics Engineers of Korea TC
• /
• v.37 no.7
• /
• pp.9-17
• /
• 2000

Determining the position and velocity of mobiles is an important issue for efficient handoff and channel allocation in microcell structure. Our early work proposes a technique for estimating the mobile location in the microcellular architecture. This process is based on the three step position estimation which determines the mobile position by gradually reducing the area of the mobile position. Using three step method, the estimator first estimates the locating sector in the sector estimation step, then estimates the locating zone in the zone estimation step, and then finally estimates the locating block in the block estimate step. But this scheme is prone to errors when the mobile is located in the boundary of sectors or tracks. In this paper we propose the enhanced scheme to reduce the estimation error.

• Journal of the Korea Institute of Military Science and Technology
• /
• v.13 no.4
• /
• pp.551-560
• /
• 2010

In this paper, we suggest a localization method of factors affecting the accuracy of Air-to-Ground weapon delivery. The proposed method, called FBEL(Factor-Based Error Localization), is based on the fault localization technique widely utilized in the realm of software engineering field. FBEL localizes the major factors affecting the performance of weapon delivery. To analyze the effectiveness and the applicability of FBEL, we applied FBEL to real firing data and got the major factors caused the errors. We expect that the method could contribute to improve the quality of weapon delivery system. We also expect that it may aid improvement of pilot capability greatly, if it is applied to pilot firing training.