• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.1124_1125
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• 2009

이 논문에서는 멀티스트링 타입 계통연계형 3상 태양광 발전 시스템 개발 과정중 인버터 파트에 필요한 기본적인 기술들을 살펴보고 검증해 보았다. 계통연계에 필요한 위상추종제어 3상 DPLL(Digital Phase Locked Loop)과 DC 링크 전압제어 그리고 계통전류 제어기의 구조와 비간섭전류제어 등을 살펴보고 무변압기형에 사용되는 3상인버터의 L-C-L 필터 설계 방법을 살펴보고 L-C 필터와 비교하여 살펴보았다. 최종적으로 앞에서 언급하였던 제어기와 이론 등을 시뮬레이션으로 검증하였으며 현재 개발 중인 프로토타입 하드웨어 설계에 대해서도 기술하였다.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2015.11a
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• pp.341-342
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• 2015

3D printer는 현재 세계적으로 시장이 확대됨에 따라 다방면으로 연구가 진행되고 있다. 이중에서 3DP (Three Dimensional Printing) 방식은 석고타입의 분말 powder가 도포된 층 위에 binder가 잉크젯 헤드를 통해 분사되어 powder 층과 층 사이를 붙여가며 형상을 제작하는 적층 방식의 일종이다. 반면 한정된 소재와 비싼 가격 때문에 보편적으로 사용하기에 한계가 있으며 대부분의 소재가 인체 유해한 성질을 보유하고 있어 활용 범위가 제한적이다. 본 연구에서는 인체 무해하고 다양한 기능이 내재된 생체 친화용 기능성 소재를 개발하고 3DP 방식의 프린터 제작을 통해 생체 친화적 기능성 형상을 제작하는 기술을 개발하였다.

• Journal of Energy Engineering
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• v.11 no.3
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• pp.224-229
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• 2002

During the operation of Circulating Fluidized Bed Combustion Boiler, defluidization is mainly caused by the formation of clinker. The clinker is made of components of Si, Fe, Ca, etc. However, although the defluidization is widely researched, the major factor has not been validated yet clearly. In this study, in the view of the shape and the arrangement of nozzles at a distributor (type 1, type 2), the formation of clinker is examined by CFD calculations and an improved nozzle design is proposed.

• The Journal of the Convergence on Culture Technology
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• v.8 no.3
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• pp.435-439
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• 2022

Many of the industry was changed because of the pandemic of covid 19. It combined with the tendency of modern people to pursue convenience. The industry of Cosmetics also changed business channel from offline to online. Before, people can not get suggestions after they complete the survey. This paper research how to suggest some cosmetics products with their skin type and skin data. We will develop Beauty Concierge system that can get suggestion after the survey. It's will make people attend activity and can make more benefit to the people.

• The Journal of Korean Academy of Prosthodontics
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• v.54 no.3
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• pp.259-266
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• 2016

In edentulous mandible, implant supported overdenture was considered as a first treatment option. Konus type attachment supplies rigid support and cross arch stabilization so that more favorable force transmission and distribution can be attained. In the dentistry, computer aided design-computer aided manufacturing (CAD-CAM) system makes it possible to fabricate restorations with high precision and effectiveness. Recently, Palladium-silver (Pd-Ag) alloy which is millable has been developed. This article presents that application of CAD-CAM Konus type attachment can be provide satisfactory stability and function on four-implant supported mandibular overdenture.

• Journal of Advanced Navigation Technology
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• v.18 no.2
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• pp.191-199
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• 2014

Recently, researches to facilitate utilization by small and medium business (SMB) of cloud computing and big data paradigm, which is the booming adoption of IT area, has been on the increase. As one of these efforts, in this paper, we design and implement the prototype to tentatively build up Hadoop cluster under private cloud infrastructure environments. Prototype implementation are made on each hardware type such as single board, PC, and server and performance is measured. Also, we present the integrated verification results for the data analysis performance of the analysis software system running on top of realized prototypes by employing ASA (American Standard Association) Dataset. For this, we implement the analysis software system using several open sources such as R, Python, D3, and java and perform a test.

• Journal of Korea Game Society
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• v.15 no.5
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• pp.131-142
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• 2015

A self-driving car is an autonomous vehicle capable of fulfilling the main transportation capabilities of a traditional car. It must be capable of sensing its environment and navigating without human input. In this paper, we design the agent that can simulate these self-driving cars and develop a prototype for it. To do this, we analyze the requirements for the self-driving car, and then the agent is designed to be suitable for traditional multi-agent system. The key point of the design is that agents move along the steering forces only. The prototype of the designed agent was implemented by using Unity 3D. From simulation results using the prototype, movements of the agents were very realistic. However, in the case of increasing the number of the agent the performance was seriously degraded, and so the alternatives of the problem were suggested.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.16 no.7
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• pp.1495-1504
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• 2012

This paper proposes an algorithm to classify and analyze facial features such as eyebrow, eye, mouth and chin based on the geometric features of the face. As a preprocessing process to classify and analyze the facial features, the algorithm extracts the facial features such as eyebrow, eye, nose, mouth and chin. From the extracted facial features, it detects the shape and form information and the ratio of distance between the features and formulated them to evaluation functions to classify 12 eyebrows types, 3 eyes types, 9 mouth types and 4 chine types. Using these facial features, it analyzes a face. The face analysis algorithm contains the information about pixel distribution and gradient of each feature. In other words, the algorithm analyzes a face by comparing such information about the features.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.348-348
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• 2012

CTF 메모리 소자는 높은 집적도와 낮은 구동전압과 CMOS 공정을 그대로 사용할 수 있고 비례 축소가 용이하다는 장점을 가지기 때문에 많은 연구가 진행되고 있다. CTF 메모리의 게이트 크기가 30 nm 이하로 작아짐에 따라 메모리 셀 간의 간섭이 매우 크게 증가하는 문제점이 있다. 이 문제점을 해결하기 위해 낸드 플래쉬 메모리 소자에서 셀 간 간섭 현상에 대한 많은 연구가 진행되고 있다. 본 연구에서는 $TaN-Al_2O_3-SiN-SiO_2-Si$ (TANOS) 플래쉬 메모리 소자에서 recess field의 모양에 따른 전기적 특성을 시뮬레이션 하였다. Recess field는 각 전하 트랩 층의 word 라인 방향에 존재하며 셀 간 간섭 효과를 줄이고 메모리 소자의 coupling ratio를 증가시키는 효과를 가지고 있다. TANOS 메모리 소자의 게이트 크기를 25 nm 에서 40 nm 로 변화하면서 round 타입의 recess field와 angular 타입의 recess field 에 대한 전기적 특성을 3차원 시뮬레이션 툴인 Sentaurus를 이용하여 시뮬레이션 하였다. Recess field를 가지지 않은 TANOS 메모리의 셀 간 간섭 효과는 게이트의 크기가 40 nm에서 25 nm 줄어들 때 많이 증가한다. 시뮬레이션된 결과에서 recess field의 모양에 상관없이 깊이가 늘어남에 따라 셀 간 간섭효과가 감소하였다. Recess field 의 깊이가 커짐에 따라 surrounding area가 늘어나 coupling ratio 가 증가하였다. Recess field 의 깊이가 증가함에 따라 프로그램 동작 시 트랩 층에 트랩 되는 전하의 수가 증가하고 recess field가 Si 기판의 표면에 가까이 위치할수록 coupling ratio, 드레인 전류 및 동작속도가 증가하였다. Recess field의 모양에 달리 하였을 때는 round 타입의 recess field를 가진 플래쉬 메모리 디바이스가 angular 타입의 recess field를 가진 소자와 비교하여 채널 표면의 잉여 전계가 감소하여 subthreshold leakage current 감소하였다. 본 연구의 시뮬레이션 결과는 수십 나노 스케일의 CTF 낸드 플래쉬 메모리 전기적 특성을 이해하는데 도움을 줄 것이다.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.45 no.4
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• pp.22-30
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• 2008

In this paper, we deal with modulation classification method using WT capable of classifying incident digital signals without a priori information. These key features should have good properties of sensitive with modulation types and insensitive with SNR variation. The 4 key features for modulation recognition are selected using WT coefficients, which have the property of insentive to the changing of noise. The numerical simulations for classifying 8 digital modulation types using these features are peformed. The numerical simulations of the 3 types (i.e. DTC, MDC, and SVMC) of modulation classifiers are performed the investigation of classification accuracy and execution time to design the modulation classification module in software radio. The simulation result indicated that the execution time of MDC and DTC was best and MDC and SVMC showed good classification performance.