• Journal of the Korean Institute of Intelligent Systems
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• v.24 no.2
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• pp.123-128
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• 2014

This paper presents the study about MGV(Magnetic guidance vehicle) with up-and-down rotating type differential drive unit. Previous MGV needs the landmarks to get the driving information and additional sensor to recognize the landmarks except for localization sensor. Previous MGV requires at least 2 drive units when common fixed differential drive unit is used because it occurs the problems with driving control and localization error from imbalance of the MGV's weight. To solve such problems, we propose the MGV using up-and-down rotating type differential drive unit. Proposed MGV recognizes the driving information from the pattern which is consisted of both pole of magnet without landmarks and additional sensors, and it control the backward movement using up-and-down rotating type differential drive unit instead of common drive units. Proposed MGV considers KF(Kalman filter) to improve the localization accuracy. To verify the performance of proposed method, we designed MGV for the experiment. As the results, we can confirm the performance of propoesed method to recognize the pattern and to control the backward movement. With respect to localization, proposed method has the less RMSE about 5.6904 mm than previous method.

• Journal of the Microelectronics and Packaging Society
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• v.31 no.3
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• pp.18-23
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• 2024

Nanoimprint lithography (NIL) is widely used to form structures ranging from micro to nanoscale due to its advantage of generating high-resolution patterns at a low process cost. However, most NIL processes require the use of imprint resists and external elements such as ultraviolet light or heat, necessitating additional post-processes like etching or metal deposition to pattern the target material. Furthermore, patterning on flexible and/or non-planar films presents significant challenges. This study introduces an extreme pressure imprint lithography (EPIL) process that can form micro-/nano-scale patterns on the surface of a flexible rubber magnet composite (RMC) film at room temperature without an etching process. The EPIL technique can form ultrafine structures over large areas through the plastic deformation of various materials, including metals, polymers, and ceramics. In this study, we demonstrate the process and outcomes of creating a variety of periodic structures with diverse pattern sizes and shapes on the surface of a flexible RMC composed of strontium ferrite and chlorinated polyethylene. The EPIL process, which allows for the precise patterning on the surface of RMC materials, is expected to find broad applications in the production of advanced electromagnetic device components that require fine control and changes in magnetic orientation.

• The KIPS Transactions:PartC
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• v.10C no.5
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• pp.647-656
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• 2003

In Webspace, mining traversal patterns is to understand user's path traversal patterns. On this mining, it has a unique characteristic which objects (for example, URLs) may be visited due to their positions rather than contents, because users move to other objects according to providing information services. As a consequence, it becomes very complex to extract meaningful information from these data. Recently discovering traversal patterns has been an important problem in data mining because there has been an increasing amount of research activity on various aspects of improving the quality of information services. This paper presents a Dynamic Link Recommendation (DLR) algorithm that recommends link sets on a Web site through mining frequent traversal patterns. It can be employed to any Web site with massive amounts of data. Our experimentation with two real Weblog data clearly validate that our method outperforms traditional method.

• Journal of Korea Multimedia Society
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• v.7 no.9
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• pp.1255-1262
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• 2004

This paper proposes a pattern matching algorithm which is useful for pattern matching and verification of images which includes noises. This algorithm is based on the feature that the signal energy of image is concentrated in a small frequency region in Fourier domain. The proposed method extracts the small parts around origins and compares the regions. Specifically, the parts around origins are extracted and subtracted, and finally experimental threshold is adopted for pattern matching. In particular, the proposed algorithm is useful for the images which includes noises because the noises are distributed in the high frequency region generally, and the method extracts the low frequency region only. Experimental result shows the method recognize ten standard images and three images includes various noises. This method shows the performance which is equal to or better than that of Phase Only Correlation in some cases.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.1
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• pp.666-670
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• 2015

This paper presents radiation pattern reconfigurable antenna for Fitbit Flex wristband which detects vital signal. Also, the paper presents Specific Absorption Rate (SAR) from the loop-dipole radiation pattern reconfigurable antenna based on the position of human body. The proposed loop-dipole radiation pattern reconfigurable antenna produces two opposite side direction radiation pattern using two RF switches. The resonant frequency of the radiation pattern reconfigurable antenna is Bluetooth communication bandwidth (2.4 - 2.485 GHz) and the maximum gain of the proposed antenna is 1.96 dBi. The proposed antenna satisfied the standard SAR value of 1.6 W/kg in 1 g tissue of the human body when the Bluetooth communication input average power of 0.04 W is excited to five parts of human body (head, chest, stomach, back, wrist). The maximum SAR value of in this simulation is presented in the part of head.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.482-482
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• 2013

반도체 소자의 미세화와 더불어 세정공정의 중요성이 차지하는 비중이 점점 커지고, 이에 따라 세정 기술 개발에 대한 요구가 증대되고 있다. 기존 세정 기술은 화학약품 위주의 습식 세정 방식으로 표면 손상, 화학 반응, 부산물, 세정 효율 등 여러 가지 어려움이 있다. 따라서 건식세정 방식이 활발하게 도입되고 있으며 대표적인 것이 에어로졸 세정이다. 에어로졸 세정은 기체상의 작동기체를 이용하여 에어로졸을 형성하고 표면 오염물질과 직접 물리적 충돌을 함으로써 세정한다. 하지만 이 또한 생성되는 에어로졸 내 발생 입자로 인해 패턴 손상이 발생하며 이러한 문제점을 극복하기 위하여 본 연구에서는 가스클러스터 장치를 이용한 세정 특성 평가에 관한 연구를 수행하였다. 가스 클러스터란 작동기체의 분자가 수십에서 수백 개 뭉쳐 있는 형태를 뜻하며 이렇게 형성된 클러스터는 수 nm 크기를 형성하게 된다. 그리고 짧은 시간의 응축에 의해 수십 nm 크기까지 성장하게 된다. 에어로졸 세정과 다르게 클러스터가 성장할 환경과 시간을 형성하지 않음으로써 작은 클러스터를 형성하게 되며 이로 인해 패턴 손상을 최소화 하고 상대적으로 높은 효율로 오염입자를 제거하게 된다. 클러스터 세정 장비를 이용한 표면 처리는 충돌에 의한 제거에 기반한다. 따라서 생성 및 가속되는 클러스터로부터 대상으로 전달되는 운동량의 정도가 세정 특성에 영향을 미치며 이는 생성되는 클러스터의 크기에 종속적이다. 생성 클러스터의 크기 분포는 분사 거리, 유량, 분사 각도, 노즐 냉각 온도 등의 변수에 관한 함수이다. 따라서 본 연구에서는 $CO_2$ 클러스터를 이용한 세정 특성을 평가하기 위하여 이러한 변수에 따라서 오염 입자의 종류, 크기에 따른 PRE (particle removal efficiency)를 평가하고 다양한 선폭의 패턴을 이용하여 손상 실험을 수행하였다. 제거 효율에 사용된 입자는 $CeO_2$와 $SiO_2$이며, 각각 30, 50, 100, 300 nm 크기를 정량적으로 오염시킨 쿠폰 웨이퍼를 제조하여 세정 효율을 평가하였다. 정량적 오염에는 SMPS (scanning mobility particle sizer)를 이용한 크기 분류와 정전기적 입자 부착 시스템이 사용되었다. 또한 패턴 붕괴 평가에는 35~180 nm 선폭을 가지는 Poly-Si 패턴을 이용하였다. 실험 결과 클러스터 형성 조건에 따라 상대적으로 낮은 패턴 붕괴에서 95% 이상의 높은 오염입자 제거효율을 전반적으로 보이는 것을 확인할 수 있었다. 따라서 이론적 계산에 기반하여 세정에 요구되는 클러스터 크기를 가정하고, 이를 통하여 세정에 적용할 경우 높은 기존 세정 방법의 단점을 보완하면서 높은 세정 효율을 가지는 대체 세정 방안으로 이용할 수 있음을 확인하였다.

• Journal of Internet Computing and Services
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• v.5 no.1
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• pp.1-13
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• 2004

The effect of Application system with class units is not sufficient because of independency and reuse of Component elements due to component abstraction based on only source code. Therefore We need to apply design pattern approach to represent not only the problem abstraction but also information and relationship between system elements for generic solutions of specific domain, Also, it is essential to software reverse engineering acquiring the correct understandings of the system through examining the existing systems and utilizing the acquired knowledges as reusable resources. In this paper, the extraction algorithm with JAVA and the validity of applying reverse engineering with extracting design patterns from source codes of the existing object-oriented system; are devised. The architecture of automatic tool is designed and implemented for 1) automatic extraction of design patterns and 2) reuse tool for retrieving, editing and rebuilding of design patterns.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.38 no.3
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• pp.269-281
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• 2001

This thesis deals with a novel font-dependent Hangul recognition algorithm invariant to position translation, scaling, and rotation using circular pattern vectors. The proposed algorithm removes noise from input letters using binary morphology and generates the circular pattern vectors. The generated circular pattern vectors represent spatial distributions on several concentric circles from the center of gravity in a given letter. Then the algorithm selects the letter minimizing the distance between the reference vectors and the generated circular pattern vectors. In order to estimate performances of the proposed algorithm, the completed Batang Hangul 2,350 letters were used as test images with scaling and rotational transformations. Experimental results show that the proposed algorithm are better than conventional algorithm using the ring projection in the recognition rates of Hangul letters with scaling and rotational transformation.

• Journal of KIISE:Databases
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• v.29 no.5
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• pp.335-346
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• 2002

LBS(Location Based Services) provide the location-based information to its mobile users. The primary functionality of these services is to provide useful information to its users at a minimum cost of resources. The functionality can be implemented through data mining techniques. However, conventional data mining researches have not been considered spatial and temporal aspects of data simultaneously. Therefore, these techniques are inappropriate to apply on the objects of LBS, which change spatial attributes over time. In this paper, we propose a new data mining technique for identifying the temporal patterns from the series of the locations of moving objects that have both temporal and spatial dimension. We use a spatial operation of contains to generalize the location of moving point and apply time constraints between the locations of a moving object to make a valid moving sequence. Finally, the spatio-temporal technique proposed in this paper is very practical approach in not only providing more useful knowledge to LBS, but also improving the quality of the services.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.8
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• pp.1901-1906
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• 2010

This classification of walking patterns is important and many kinds of applications. Therefore, we attempted to classify walking on level ground from slow walking to fast walking using a waist acceleration signal. A tri-axial accelerometer was fixed to the subject's waist and the three acceleration signals were recorded by bluetooth module at a sampling rate of 100 Hz eleven healthy. The data were analyzed using discrete wavelet transform. Walking patterns were classified using two parameters; One was the ratio between the power of wavelet coefficients which were corresponded to locomotion and total power in the anteroposterior direction (RPA). The other was the ratio between root mean square of wavelet coefficients at the anteroposterior direction and that at the vertical direction(RAV). Slow walking could be distinguished by the smallest value in RPA from other walking pattern. Fast walking could be discriminated from level walking using RAV. It was possible to classify the walking pattern using acceleration signal in healthy people.