• Transactions of the Korean Society of Mechanical Engineers A
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• v.36 no.1
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• pp.73-79
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• 2012

Kiosks are widely used in drive-thru systems in parking lots or on the highway to provide various services to drivers. However, the driver must stop at an exact location to access the kiosk, since its panel is fixed. In order to improve the kiosk accessibility, in this study we developed a manipulator that can adjust the position of the kiosk panel. The number of active joints was minimized to lower the cost, whereas a parallelogram mechanism and passive joints were adopted to increase its convenience for the users. Furthermore, a safety mechanism using springs and a cam was designed to ensure the safety of the user in the case of an emergency. The performance of the position controller and the safety mechanism were verified through various tests. In addition, the proposed collision reaction strategy improved the safety performance of the kiosk system.

• Journal of the Korea Society of Computer and Information
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• v.29 no.1
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• pp.151-161
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• 2024

In this paper, we develop 'the Danger Map' of a workplace to identify risk and harmful factors by analyzing images of each process within the manufacturing plant site using artificial intelligence (AI). We proposed a system that automatically derives 'the risk and safety levels' based on the frequency and intensity derived from this Danger Map in accordance with actual field conditions and applies them to similar manufacturing industries. In particular, in the traditional evaluation method of manually evaluating the risk of a workplace using Excel, the risk level for each risk and harmful factor acquired from the video is automatically calculated and evaluated to ensure safety through the system and calculate the safety level, so that the company can take appropriate actions accordingly. and measures were prepared. To automate safety calculation and evaluation, 'Heinrich's law' was used as a model, and a 5X4 point evaluation scale was calculated for risky behavior patterns. To demonstrate this system, we applied it to a casting factory and were able to save 2 people the time and labor required to calculate safety each month.

• Proceedings of the KWS Conference
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• 2010.05a
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• pp.49-49
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• 2010

용접은 산업계의 기계 조립 및 접합을 위한 공정의 주요한 작업으로 조선, 중공업, 건설 등 산업현장에서 사람에 의한 수동적인 작업으로 대부분 수행된다. 이러한 용접 작업을 수행하는 용접 기술자는 산업 현장 훈련원과 직업 교육 학교에서 양성되지만 용접 훈련 과정은 실습 초보자에게 위험하고, 장시간 교육하기에 어려울 뿐 아니라 재료 낭비, 의사 소통의 한계, 즉석 결과 평가의 한계, 공간부족 등 다양한 문제가 있다. 그러므로, 안전하고 반복적인 실습 환경 제공하고 장시간 및 다수 교육참여 지원 등이 가능한 시스템을 구축하여 숙련된 우수 인력 조기 확보와 훈련 비용을 절감할 필요가 있다. 본 논문에서는 실제와 동일한 상호작용을 제공할 뿐만 아니라 고품질로 훈련 환경을 가시화하여 용접 상황을 동일하게 모사하는 가상 현실 기반 용접 훈련 시뮬레이터를 제시한다. 이 시스템은 용접의 형상과 환경의 고품질 가시화, 경험 DB를 통한 용접의 비드 형상 데이터 획득, 용접 토치를 이용하는 사용자 상호작용, 용접 훈련 결과 평가 및 최적 작업 가이드, 용접 콘텐츠 저작, 다양한 용접 훈련을 가시화하는 하드웨어 플랫폼으로 구성된다. 고품질 가상 용접 가시화는 경험 DB 기반 비드 형상 데이터와 신경회로망을 이용한 비드 형상 예측을 통해 실시간 비드 표현이 이루어지며 쉐이더 기반 고품질 모재 및 비드 표현, 아크 불꽃 효과 표현을 포함한다. 사용자 상호작용은 현장 작업 도구와 일치된 토치 인터페이스와 위치추적을 이용하여 토치의 작업각, 진행각, 속도, 거리 등을 반영할 수 있으며 진동과 소리 등 용접 훈련의 사실적 상호작용도 재현하였다. 용접 훈련 평가 및 최적 작업 가이드는 훈련자의 용접속도, 거리, 각도 등의 사용자 작업 결과를 그래픽으로 표현하고, 애니메이션을 통한 훈련 자세를 추후 분석할 수 있도록 하였고, 가상토치, 기준선, 수치계기 등을 이용한 최적 작업 훈련 가이드 제시하였다. 훈련 콘텐츠 저작은 메뉴UI 기반으로 용접의 전류, 전압 등의 조건과 상황을 선택하도록 제시하였고, 하드웨어 플랫폼은 워크벤치형 입체 디스플레이 방식으로 용접 환경을 가시화하였고, 위, 정면, 아래보기 등 다양한 용접 자세 변경을 지원 할 수 있도록 구축하였다. 이러한 가상현실 기반 훈련 시뮬레이터는 아크열 발생에 따른 장시간 훈련의 어려움을 극복할 수 있고, 다양한 실습 환경을 바꾸어 가며 반복적인 훈련이 가능하고, 실 재료를 사용하지 않아 재료의 낭비를 줄일 수 있는 환경 친화적인 안전하고 효율적인 훈련 실습 환경을 제공할 수 있다.

• Journal of Energy Engineering
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• v.7 no.1
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• pp.96-102
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• 1998

The use of computers as part of nuclear safety systems elicits additional requirements-software verification and validation (v/v), hardware qualification-not specifically addressed in general industry fields. The computer used in nuclear power plants is a system that includes computer hardware, software, firmware, and interfaces. To develop the computer systems graded with nuclear safety class, the developing environments have to be required in advance and the developed software have to be verified and validated in accordance with nuclear code and standards. With this requirements, the test facility for Inadequate Core Cooling Monitoring System (ICCMS) as one of safety systems in the nuclear power plants was developed. The test facility consists of three(3) parts such as Input/Output (I/O) simulator, Plant Data Acqusition System (PDAS) cabinets and supervisory computer. The performance of the system was validated by manual test procedure.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.1B
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• pp.1-10
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• 2003

An EPON which is going on standardization in IEEE 802.3ah, is tree topology consists of a OLT and multiple ONU using passive optical components, so this network is susceptible to variable security threats - eavesdropping, masquerading, denial of service and so on. In this paper, we design a security protocol supporting authentication and confidentiality services in MAC layer in order to prevent these security threats and to guarantee secure data exchange The designed security protocol introduce public-key based authentication and key management protocols for efficient key management, and choose Rijndael algorithm, which is recent standard of AES, to provide the confidentiality of EPON Proposed authentication and key management protocols perform authentication and public-key exchange at a time, and are secure protocols using derived common cipher key by exchanging public random number To implement the designed security protocol, we propose the procedures of authentication and public-key exchange, session key update, key recovery. This proposed protocol is verified using unknown session key, forward secrecy, unknown key-share, key-compromise impersonation.

• Journal of the Korea institute for structural maintenance and inspection
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• v.27 no.5
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• pp.30-39
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• 2023

Large dams, which are critical infrastructures for disaster prevention, are exposed to various risks such as aging, floods, and earthquakes. Better dam safety inspection and diagnosis using digital transformation technologies are needed. Traditional visual inspection methods by human inspectors have several limitations, including many inaccessible areas, danger of working at heights, and know-how based subjective inspections. In this study, drone photogrammetry was performed on two large dams to evaluate the applicability of digital data-based dam safety inspection and propose a data management methodology for continuous use. High-quality 3D digital models with GSD (ground sampling distance) within 2.5 cm/pixel were generated by flat double grid missions and manual photography methods, despite reservoir water surface and electromagnetic interferences, and severe altitude differences ranging from 42 m to 99.9 m of dam heights. Geometry profiles of the as-built conditions were easily extracted from the generated 3D mesh models, orthomosaic images, and digital surface models. The effectiveness of monitoring dam deformation by photogrammetry was confirmed. Cracks and deterioration of dam concrete structures, such as spillways and intake towers, were detected and visualized efficiently using the digital 3D models. This can be used for safe inspection of inaccessible areas and avoiding risky tasks at heights. Furthermore, a methodology for mapping the inspection result onto the 3D digital model and structuring a relational database for managing deterioration information history was proposed. As a result of measuring the labor and time required for safety inspection at the SYG Dam spillway, the drone photogrammetry method was found to have a 48% productivity improvement effect compared to the conventional manpower visual inspection method. The drone photogrammetry-based dam safety inspection is considered very effective in improving work productivity and data reliability.

• Journal of Internet Computing and Services
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• v.20 no.4
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• pp.91-102
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• 2019

In autonomous driving systems, the ability to classify pedestrians in images captured by cameras is very important for pedestrian safety. In the past, after extracting features of pedestrians with HOG(Histogram of Oriented Gradients) or SIFT(Scale-Invariant Feature Transform), people classified them using SVM(Support Vector Machine). However, extracting pedestrian characteristics in such a handcrafted manner has many limitations. Therefore, this paper proposes a method to classify pedestrians reliably and effectively using CNN's(Convolutional Neural Network) deep features and transfer learning. We have experimented with both the fixed feature extractor and the fine-tuning methods, which are two representative transfer learning techniques. Particularly, in the fine-tuning method, we have added a new scheme, called M-Fine(Modified Fine-tuning), which divideslayers into transferred parts and non-transferred parts in three different sizes, and adjusts weights only for layers belonging to non-transferred parts. Experiments on INRIA Person data set with five CNN models(VGGNet, DenseNet, Inception V3, Xception, and MobileNet) showed that CNN's deep features perform better than handcrafted features such as HOG and SIFT, and that the accuracy of Xception (threshold = 0.5) isthe highest at 99.61%. MobileNet, which achieved similar performance to Xception and learned 80% fewer parameters, was the best in terms of efficiency. Among the three transfer learning schemes tested above, the performance of the fine-tuning method was the best. The performance of the M-Fine method was comparable to or slightly lower than that of the fine-tuningmethod, but higher than that of the fixed feature extractor method.

• Journal of Digital Convergence
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• v.12 no.7
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• pp.37-47
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• 2014

This study applies Policy Streams and Expert Group Standing Change Framework (PSECF) proposed by SangJung Park and Chan KOH to analyze the Roh's Participatory government's decision making process on the wartime Operational Control (OPCON) transition. PSECF case study's results are as follows: Strong commitments of the former president Roh Moohyun and the progressive National Security Committee (NSC) were primary drivers in the policy developing process. But military expert groups such as the Ministry of National Defense (MND) and the Joint Chiefs of Staffs (JCS) were thoroughly excluded due to their passive role against the wartime OPCON transition. After the policy resolution, the standing of expert groups changed: the standing of advocate effects, the former progressive NSC who led the wartime OPCON transition in the Roh's Participatory government, went down but the conservatives such as ROK MND and JCS improve their standing because the conservative government kicks off 8 months later from the policy decision. In conclusion, the proposed PSECF through the Roh's Participatory government's case-study is worthy as an explanatory framework for high level national policies.

• The Transactions of the Korean Institute of Power Electronics
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• v.14 no.2
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• pp.160-167
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• 2009

To detect islanding mode when the grid is being tripped is a major safety issue in the Utility Interactive Photo Voltaic (UIPV) system. In this paper, analytical design method is suggested for AFD & RPV method under IEEE 929-2000 recommended islanding test condition. We have discussed that there is a same point. we injected reactive component of the current by AFD & RPV methods, but the current reference generated is other waveform. Possible if amount of reactive components in this methods are same each method, there is happened same rates frequency variation. To verify the validity of the analytical comparison, this paper presents simulation and experimental results from single phase, 3[kW] inverter for the transformerless UIPV system.

• Proceedings of the Korean Society of Computer Information Conference
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• 2020.07a
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• pp.259-260
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• 2020

기존의 전동휠체어를 사용하는 약자 또는 중증 장애인 등 지체(肢體)가 불편한 사람들이 휠체어 사용 시 생기는 문제점을 해소할 목적으로 시작되었다. 이는 전동휠체어가 보행 기구임에도 자동차에 준하는 교통사고에 대해 무방비하게 노출되고, 중증 장애인에 대한 이동권 보장이 아직 미흡하여 생기는 문제이다. 따라서 본 연구에서는 이러한 문제로 인한 불편함을 해소하고자 아이트래킹을 이용한 스마트 전동휠체어 기술을 적용하고자 한다. 루게릭병 등으로 인해 지체(肢體)의 움직임에 제한이 있는 사람들에게 보호자가 밀어주는 휠체어에 의존하는 것이 아닌 Eye-Tracker를 이용한 시선 추적(Eye-Tracking) 기술로 휠체어 동작이 가능하다. Web-Cam과 라즈베리 파이를 통해 얻은 전·후·좌·우의 영상정보를 디스플레이 화면에 송출한다. 그 후 Eye-Tracking 기술을 이용해 디스플레이 화면에 표시된 전·후·좌·우 이동에 관한 UI(User Interface)룰 사용자가 송출된 영상을 보면서 눈의 움직임만으로 선택해 휠체어의 방향을 제어한다. 또한 전동휠체어의 조작 실수로 다른 행인 또는 장애물과 충돌하는 문제점을 초음파 센서를 이용하여 일정 거리 내에 사물이나 사람이 있을 경우 디스플레이 화면에 경고표시 및 경고음, 각 초음파 센서 위치에 맞는 LED작동으로 사용자들에게 추돌 위험경고와 함께 장애물의 위치파악이 가능하도록 한다. 따라서 스마트 전동휠체어를 통하여 수동적인 움직임이 아닌 능동적이고, 초음파 센서로 인해 안전한 이동이 가능하게 한다.