• Journal of the Microelectronics and Packaging Society
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• v.19 no.1
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• pp.81-87
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• 2012

This paper focuses on three-dimensional measurement system of micro balls on micro Ball-Grid-Array(BGA) packages in-line. Most of visual inspection system still suffers from sophisticate reflection characteristics of micro balls. For accurate shape measurement of them, a specially designed visual sensor system is proposed under the sensing principle of phase shifting moire interferometry. The system consists of a pattern projection system with four projection subsystems and an imaging system. In the projection system, four subsystems have spatially different projection directions to make target objects experience the pattern illuminations with different incident directions. For the phase shifting, each grating pattern of subsystem is regularly moved by PZT actuator. To remove specular noise and shadow area of BGA balls efficiently, a compact multiple-pattern projection and imaging system is implemented and tested. Especially, a sensor fusion algorithm to integrate four information sets, acquired from multiple projections, into one is proposed with the basis of Bayesian sensor fusion theory. To see how the proposed system works, a series of experiments is performed and the results are analyzed in detail.

• Korean Journal of Optics and Photonics
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• v.35 no.3
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• pp.107-114
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• 2024

In this study, the feasibility of using the covariance-matrix-adaptation-evolution-strategy (CMA-ES) algorithm in a multichannel coherent-beam-combining (CBC) system was experimentally verified. We constructed a multichannel CBC system utilizing a spatial light modulator (SLM) as a multichannel phase-modulator array, along with a coherent light source at 635 nm, implemented the stochastic-parallel-gradient-descent (SPGD) and CMA-ES algorithms on it, and compared their performances. In particular, we evaluated the characteristics of the CMA-ES and SPGD algorithms in the CBC system in both 16-channel rectangular and 19-channel honeycomb formats. The results of the evaluation showed that the performances of the two algorithms were similar on average, under the given conditions; However, it was verified that under the given conditions the CMA-ES algorithm was able to operate with more stable performance than the SPGD algorithm, as the former had less operational variation with the initial phase setting than the latter. It is emphasized that this study is the first proof-of-principle demonstration of the CMA-ES phase-control algorithm in a multichannel CBC system, to the best of our knowledge, and is expected to be useful for future experimental studies of the effects of additional channel-number increments, or external-phase-noise effects, in multichannel CBC systems based on the CMA-ES phase-control algorithm.

• Journal of KIISE:Software and Applications
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• v.27 no.5
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• pp.521-528
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• 2000

One of the hidden problems in a domain theory is that an agent does not understand the meaning of its action. Graphplan uses mutex to improve efficiency, but it does not understand negation and suffers from a redundancy problem. Introducing a negative function not in IPP partially helps to solve this kind of problem. However, using a negative function comes with its own price in terms of time and space. Observing that a human utilizes opposite concept to negate a fact based on MDL principle, we hypothesize that using a positive atom rather than a negative function to represent a negative fact is a more efficient technique for building an intelligent agent. We show empirical results supporting our hypothesis in IPP domains. To autonomously learn the human-like concept, we generate a cycle composed of opposite operators from a domain theory and extract opposite literals through experimenting with the operators.

• Journal of the Institute of Electronics Engineers of Korea TE
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• v.39 no.3
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• pp.28-34
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• 2002

This paper describes embedding non-linearly watermark data in the components of pixel intensities in the spatial domain of an image. The principle of the proposed method is that when an image is segmented regularly to the blocks, the pixels of the block have the non-linear properties without any similarity. That is, for the block with strong non-linear property human can't feel the visual different to the modified pixel values, on the other hand for the block with weak non-linear property human can feel the visual different to the a little modified pixel values. Thus we could embed the watermark data according to the non-linear property of the blocks. As the result of the simulation, against some general image processing attacks our algorithm could keep robust and be responsible for the copyright certainly. 

• Proceedings of the Korean Vacuum Society Conference
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• 2015.08a
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• pp.91-91
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• 2015

반도체 공정의 발전에 의해 최근 생산되는 메모리 등은 십 수 나노미터까지 좁아진 선 폭을 갖게 되었다. 이러한 이유로, 기존에는 큰 문제를 발생시키지 않던 나노미터 영역의 입자들이 박막 증착 공정과 같은 반도체 제조공정 수율을 저감시키게 되었다. 따라서 오염입자의 유입을 막거나 제어하기 위해 transmission electron microscopy (TEM)나 scanning electron microscopy (SEM)과 같은 전자현미경을 활용한 비 실시간 입자 측정 방법 및 광원을 이용하는 in-situ particle monitor (ISPM) 및 전기적 이동도를 이용한 scanning mobility particle sizer (SMPS) 등 다양한 원리를 이용한 실시간 입자 측정방법이 현재 사용중에 있다. 이 중 진공 내 입자의 수농도를 측정하기 위해 개발된 particle beam mass spectrometer (PBMS) 기술은 박막 증착 공정 등 chemical vapor deposition (CVD) 방법을 이용하는 진공공정에서 활용 가능하여 개발이 진행되어 왔다. 본 연구에서는 PBMS의 한계점인 입자 밀도, 형상 등의 특성분석이 용이하도록 PBMS와 scanning electron microscopy (SEM), 그리고 energy dispersive spectroscopy (EDS) 기술을 결합하여 입자의 직경별 개수농도, 각 입자의 형상 및 성분을 함께 측정 가능하도록 하였다. 협소한 반도체 제조공정 내부 공간에 적용 가능하도록 기존 PBMS 대비 크기 또한 소형화 하였다. 각 구성요소인 공기역학 집속렌즈, electron gun, 편향판, 그리고 패러데이 컵의 설치 및 물리적인 교정을 진행한 후 입자발생장치를 통해 발생시킨 sodium chloride 입자를 상압 입자 측정 및 분류장치인 SMPS 장치를 이용하여 크기별로 분류시켜 압력차를 통해 PBMS로 유입시켜 측정을 진행하였다. 나노입자의 입경분포, 형상 및 성분을 측정결과를 토대로 장치의 측정정확도를 교정하였다. 교정된 장치를 이용하여 실제 박막 증착공정 챔버의 배기라인에서 발생하는 입자의 수농도, 형상 및 성분의 복합특성 측정이 가능하였으며, 최종적으로 실제 공정에 적용가능하도록 장치 교정을 완료하였다.

• The Transactions of the Korea Information Processing Society
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• v.4 no.1
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• pp.137-148
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• 1997

Diagnostic problem solving is a major application area of knowledge-based systems research. However, most of the current approaches, both heuristic and model-based, are designed to identify single faults, and do not generalize easily to multiple fault diagnosis without exhibiting exponential behavior in the amount of computation required. In this paper, we employ a decomposition approach based on system configuration to generate an efficient algorithm for multiple fault diagnosis. The basic idea of the algorithm is to reduce the inherent combinatorial explosion that occurs in generating multiple faults by partitioning the circuit into groups that correspond to output measurement points. Rules are multiple faults by partitioning the circuit into groups that correspond to output measurement points. rules are developed for combining candidates from individual groups, and forming consistent sets of minimal candidates.

• Journal of KIISE:Software and Applications
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• v.27 no.4
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• pp.412-421
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• 2000

In spite that the main contents of mathematical and scientific learning are understanding principles and their applications, most of existing educational softwares are based on rote learning, thus resulting in limited educational effects. In the artificial intelligence research, some progress has been made in developing automatic tutors based on proving and simulation, by adapting the techniques of knowledge representation, search and inference to the design of tutors. However, these tutors still fall short of being practical and the turor, even a prototype model, for learning problem solving is yet to come out. The geometry problem-solving tutor proposed by this research involves dynamic inference performed in parallel with learning. As an ontology for composing the problem space within a real-time setting, we have employed the notions of propositions, hypotheses and operators. Then we investigated the mechanism of interactive learning of problem solving in which the main target of inference involves the generation and the test of these components. Major accomplishment from this research is a practical model of a problem tutor embedded with a series of inference techniques for algebraic manipulation, which is indispensable in geometry problem solving but overlooked by previous research. The proposed model is expected to be applicable to the design of problem tutors in other scientific areas such as physics and electric circuitry.

• Journal of Advanced Navigation Technology
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• v.18 no.3
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• pp.201-208
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• 2014

Due to diversification of ships and limited space of pier, when ships come alongside the shallow water or narrow pier, sea area with small mooring facilities and floating matter is frequently applied. Through these, coming alongside the various space is capable and cost effectiveness is enhanced. However, when ships, applying small mooring facilities and floating matter, come alongside, there can be some impulse by waves between the floating things and ships which possibly leads to mass disaster. Therefore, there should be forecasts and analysis of the movement caused by waves. On this study, we develop measuring system for movement analysis of mooring and floating matters which provides base data with movement traits by measuring 3-D exercise information and acceleration at mokpo maritime university marina facility. Also, the composition and principles of the developed system is explained.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2013.10a
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• pp.165-166
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• 2013

When Coming alongside the shallow water or narrow pier, they apply sea area with small mooring facilities and Floating matter because of the diversity of ships and limitation and effective in cutting expenses. However, when ships, applying Small mooring facilities and Floating matter, come alongside, there can be some impulse by waves between the Floating things and ships which possibly leads to mass disaster. Therefore, there should be forecasts and analysis of the movement caused by waves. On this Study, it introduces the composition and principles of the developed system provides the base of the movement traits through measuring 3-D exercise data and acceleration of the Mooring and Floating matters.

• The KIPS Transactions:PartB
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• v.14B no.4
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• pp.273-280
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• 2007

This paper presents a new 3D sound toolkit called $EVE-Sound^{TM}$ that consists of pre-processing tool for environment simplification preserving sound effect and 3D sound API for real-time rendering. It is designed so that it can allow users to interact with complex 3D virtual environments by audio-visual modalities. $EVE-Sound^{TM}$ toolkit would serve two different types of users: high-level programmers who need an easy-to-use sound API for developing realistic 3D audio-visually rendered applications, and the researchers in 3D sound field who need to experiment with or develop new algorithms while not wanting to re-write all the required code from scratch. An interactive virtual environment application is created with the sound engine constructed using $EVE-Sound^{TM}$ toolkit, and it shows the real-time audio-visual rendering performance and the applicability of proposed $EVE-Sound^{TM}$ for building interactive applications with complex 3D environments.