• 대한조선학회논문집
• /
• 제36권4호
• /
• pp.105-115
• /
• 1999

선형설계는 보증속도와 재화중량을 만족하는 선체형상을 설계하는 작업이다. 선형은 선박설계 전과정을 통해 주요한 key drawing으로 작용하므로 일단 결정된 선형을 수정하는 것은 각 설계 부분에 재 작업을 요구하게 되므로, 선형결정 전에 보증속도 등의 기본 조건을 완전히 만족시키지 않으면 안 된다. 그럼에도 불구하고, 초기에 선형을 개발하는데 주어지는 기간은 매우 제한되어 있어, 성능보장을 위한 안정적인 설계 procedure를 확보하지 않으면 안 된다. 이 같은 제약과 생산성을 위한 고려사항이 같이 작용되어 일반적으로 조선소 선형개발실에서는 기존 실적선 중 유사선을 모선형으로 하여 설계대상선으로 변환하는 방법을 사용하고 있다. 또한 최근에는 초기선형 개발 단계에서 성능의 검토를 CFD에 의존하는 경우가 일반화되고 있으며, 이를 위해서는 순정도 높은 다수의 예비선형을 준비해야 한다. 제한된 개발기간 속에서 완성도 높은 다종의 예비선형을 생성하는 선형 설계 전산 시스템의 개발을 위해 본 연구에서는 모선변환을 위한 개량된 변형함수법을 개발하고, 형상요소들을 객체화하여 객체간의 연관성 설정에 의한 자동갱신 기능을 구현하였다. 이런 시스템에 의해 설계자는 원하는 형상으로 수정하는 데만 주력하면, 형상요소간의 matching 문제(consistency)는 시스템이 해결함으로서, 고정도의 선형을 신속하게 완성하는 것이 가능토록 하였다.

• 한국기록관리학회지
• /
• 제5권1호
• /
• pp.107-136
• /
• 2005

쌍방향적 정보의 교류와 접근을 가능하게 하는 정보기술의 발달을 배경으로 등장한 전자정부와 이를 지원하기 위해 제정된 전자정부법은 온라인을 통해 정부 정보를 적극적으로 제공할 것을 규정하고 있다. 이는 공공기관의 기록관리 환경에 많은 변화를 가져왔을 뿐만 아니라, 국민들이 정부정보로 접근하는 것을 더욱 확고하게 보장하였다. 공공기관이 온라인으로 정보자원을 정확하고 효율적으로 제공하도록 하는 한편, 정부가 제공하는 각종 정보자원 국민들이 편리하고 빠르게 찾을 수 있도록 돕기 위해서는 이를 지원하는 공공인프라의 구축과 함께 전자정부 메타데이터의 개발이 필요하다. 우리나라의 경우 아직 표준화된 전자정부 메타데이터는 없지만 'GILS Core 엘리먼트'가 이와 유사한 기능을 하고 있다. 하지만 GILS Core 엘리먼트는 기술 대상으로 기록을 고려하지 않은 채 개발되어 많은 문제점을 가지고 있다. 따라서 본 논문에서는 온라인으로 제공되는 정부 정보자원의 대부분을 차지할 기록의 특성을 고려하여 전자정부 메타데이터 표준을 제안하였다.

• 한국정보통신학회:학술대회논문집
• /
• 한국해양정보통신학회 2005년도 춘계종합학술대회
• /
• pp.409-412
• /
• 2005

디지털 콘텐츠는 통신, 컴퓨터, 방송, 모바일 등의 어느 한 분야에 국한되지 않고 다양한 분야에서 활용되고 있다. 디지털 콘텐츠 산업이 지식정보화 사회의 핵심 산업으로 부각되고 인터넷의 발전과, 위성통신, 방송의 보편화 글로벌 단위의 정보 인프라 구축이 진행됨에 따라 디지털 콘텐츠의 저작권 보호 및 관리를 위한 시스템이 요구되고 있다. 따라서 디지털 콘텐츠에 대한 저작권 보호를 위해 MPEG에서 MPEG-4 IPMP(Intellectual Property Management and Protection) 표준을 제정하게 되었고 계속적으로 수정 보완 하고 있다. 이에 따라 MPEG-4 기반의 IPMP 정보를 편집하고 처리하는 시스템이 필요하게 되었다. 이에 본 논문에서는 디지틸 콘텐츠의 관리 및 보호를 위하여 현재 진행중인 MPEG-4 IPMP 표준을 따르고 사용자가 IPMP 정보를 쉽게 생성 및 처리할 수 있는 폼 기반의 인터페이스를 이용하여 IPMP 정보를 효과적으로 편집하고 처리하는 MPEG-4 IPMP 시스템을 설계 및 구현하였다.

• Journal of information and communication convergence engineering
• /
• 제11권3호
• /
• pp.207-215
• /
• 2013

In this paper, we address the challenging computer vision problem of obtaining a reliable facial expression analysis from a naturally interacting person. We propose a system that combines a 3D generic face model, 3D head tracking, and 2D tracker to track facial landmarks and recognize expressions. First, we extract facial landmarks from a neutral frontal face, and then we deform a 3D generic face to fit the input face. Next, we use our real-time 3D head tracking module to track a person's head in 3D and predict facial landmark positions in 2D using the projection from the updated 3D face model. Finally, we use tracked 2D landmarks to update the 3D landmarks. This integrated tracking loop enables efficient tracking of the non-rigid parts of a face in the presence of large 3D head motion. We conducted experiments for facial expression recognition using both framebased and sequence-based approaches. Our method provides a 75.9% recognition rate in 8 subjects with 7 key expressions. Our approach provides a considerable step forward toward new applications including human-computer interactions, behavioral science, robotics, and game applications.

• Advances in aircraft and spacecraft science
• /
• 제6권2호
• /
• pp.117-144
• /
• 2019

High Altitude and Long Endurance (HALE) aircraft are capable of providing intelligence, surveillance and reconnaissance (ISR) capabilities over vast geographic areas when equipped with advanced sensor packages. As their use becomes more widespread, the demand for additional range, endurance and payload capability will increase and designers are exploring non-conventional configurations to meet the increasing demands. One such configuration is the joined-wing concept. A joined-wing aircraft is one that typically connects a front and aft wings in a diamond shaped planform. One such example is the Boeing SensorCraft configuration. While the joined-wing configuration offers potential benefits regarding aerodynamic efficiency, structural weight, and sensing capabilities, structural design requires careful consideration of elastic buckling resulting from the aft wing supporting, in compression, part of the forward wing structural loading. It has been shown already that this is a nonlinear phenomenon, involving geometric nonlinearities and follower forces that tend to flatten the entire configuration, leading to structural overload due to the loss of the aft wing's ability to support the forward wing load. Severe gusts are likely to be the critical design condition, with flight control system interaction in the form of Gust Load Alleviation (GLA) playing a key role in minimizing the structural loads. The University of Victoria Center for Aerospace Research (UVic-CfAR) has built a 3-meter span scaled and flexible wing UAV based on the Boeing SensorCraft design. The goal is to validate the nonlinear structural behavior in flight. The main objective of this research work is to perform Ground Vibration Tests (GVT) to characterize the dynamic properties of the scaled flight vehicle. Results from the experimental tests are used to characterize the modal dynamics of the aircraft, and to validate the numerical models. The GVT results are an important step towards a safe flight test program.

• International Journal of Naval Architecture and Ocean Engineering
• /
• 제12권1호
• /
• pp.491-500
• /
• 2020

The present study proposes a time domain model for the Vortex-induced Vibration (VIV) simulation of a catenary riser under the combination of the current and oscillatory flow induced by vessel motion. In this model, the hydrodynamic force of VIV comprises excitation force, hydrodynamic damping and added mass, which are taken as functions of the non-dimensional frequency and amplitude ratio. The non-dimensional frequency is related with the response frequency, natural frequency, lock-in range and the fluid velocity. The relatively oscillatory flow induced by vessel motion is taken into account in the fluid velocity. Considering that the added mass coefficient and the non-dimensional frequency can affect each other, an iterative analysis is conducted at each time step to update the added mass coefficient and the natural frequency. This model is in detail validated against the published test models. The results show that the model can reasonably reflect the effect of the added mass coefficient on the VIV, and can well predict the riser's VIV under stationary and oscillatory flow induced by vessel motion. Based on the model, this study carries out the VIV simulation of a catenary riser with harmonic vessel motion. By analyzing the bending moment near the touchdown point, it is found that under the combination of the ocean current and oscillatory flow the vessel motion may decrease the VIV response, while increase the excited frequencies. In addition, the decreasing rate of the VIV under vessel surge is larger than that under vessel heave at small vessel motion velocity, while the situation becomes opposite at large vessel motion velocity.

• Nuclear Engineering and Technology
• /
• 제53권1호
• /
• pp.148-163
• /
• 2021

Timely fault identification is important for safe and reliable operation of the electric valve system. Many research works have utilized different data-driven approach for fault diagnosis in complex systems. However, they do not consider specific characteristics of critical control components such as electric valves. This work presents an integrated shallow-deep fault diagnostic model, developed based on signals extracted from DN50 electric valve. First, the local optimal issue of particle swarm optimization algorithm is solved by optimizing the weight search capability, the particle speed, and position update strategy. Then, to develop a shallow diagnostic model, the modified particle swarm algorithm is combined with support vector machine to form a hybrid improved particle swarm-support vector machine (IPs-SVM). To decouple the influence of the background noise, the wavelet packet transform method is used to reconstruct the vibration signal. Thereafter, the IPs-SVM is used to classify phase imbalance and damaged valve faults, and the performance was evaluated against other models developed using the conventional SVM and particle swarm optimized SVM. Secondly, three different deep belief network (DBN) models are developed, using different acoustic signal structures: raw signal, wavelet transformed signal and time-series (sequential) signal. The models are developed to estimate internal leakage sizes in the electric valve. The predictive performance of the DBN and the evaluation results of the proposed IPs-SVM are also presented in this paper.

• 한국산업정보학회논문지
• /
• 제27권6호
• /
• pp.115-126
• /
• 2022

본 연구는 국내 모바일 뱅킹 애플리케이션에 대한 이용자 리뷰 데이터에 텍스트 마이닝 기법을 적용하여 중요도-만족도 분석을 시도하고, 개선의 우선순위를 도출하는 것을 목적으로 한다. 분석에는 구글 플레이스토어에서 국내 시중은행(국민은행, 신한은행, 우리은행, 하나은행), 지역은행(경남은행, 부산은행), 인터넷 은행(카카오뱅크, 케이뱅크, 토스)의 모바일 뱅킹 애플리케이션에 대한 이용자 리뷰 데이터를 활용하였으며, 주요 속성 도출 및 각 속성에 대한 중요도와 만족도 측정을 위해 토픽 모델링, 빈도분석 및 감성분석을 진행하였다. 분석 결과 '인증서비스', '기능 개선', '로그인', '속도/연결성', '시스템/업데이트' 그리고 '뱅킹서비스'가 이용자들이 모바일 뱅킹 애플리케이션을 사용할 때 느끼는 중요도가 상대적으로 높은 속성임에도 불구하고 그 만족도가 평균 수준에 미치지 못해 개선이 시급한 속성으로 나타났다.

• Journal of Veterinary Science
• /
• 제24권4호
• /
• pp.58.1-58.25
• /
• 2023

Porcine epidemic diarrhea virus (PEDV) has posed significant financial threats to the domestic pig industry over the last three decades in South Korea. PEDV infection will mostly result in endemic persistence in the affected farrow-to-finish (FTF) herds, leading to endemic porcine epidemic diarrhea (PED) followed by year-round recurrent outbreaks. This review aims to encourage collaboration among swine producers, veterinarians, and researchers to offer answers that strengthen our understanding of PEDV in efforts to prevent and control endemic PED and to prepare for the next epidemics or pandemics. We found that collaboratively implementing a PED risk assessment and customized four-pillar-based control measures is vital to interrupt the chain of endemic PED in affected herds: the former can identify on-farm risk factors while the latter aims to compensate for or improve weaknesses via herd immunity stabilization and virus elimination. Under endemic PED, long-term virus survival in slurry and asymptomatically infected gilts ("Trojan Pigs") that can transmit the virus to farrowing houses are key challenges for PEDV eradication in FTF farms and highlight the necessity for active monitoring and surveillance of the virus in herds and their environments. This paper underlines the current knowledge of molecular epidemiology and commercially available vaccines, as well as the risk assessment and customized strategies to control PEDV. The intervention measures for stabilizing herd immunity and eliminating virus circulation may be the cornerstone of establishing regional or national PED eradication programs.

• 대한두경부종양학회지
• /
• 제40권1호
• /
• pp.1-5
• /
• 2024

The Bethesda System for Reporting Thyroid Cytopathology (TBSRCT) is crucial for cytopathologists to use a standardized, category-based reporting system for thyroid fine needle aspirations and is effective for clear communication with the referring physicians. The new Bethesda System for Reporting Thyroid Cytopathology, the third edition in 2023, provides several key updates. The most important update is the assignment of only single name for each of the six diagnostic categories: (I) nondiagnostic; (II) benign; (III) atypia of undetermined significance; (IV) follicular neoplasm; (V) suspicious for malignancy; and (VI) malignant. An implied risk of malignancy (ROM) for each of six categories has been updated based on extensively published data since the second edition of TBSRTC in 2017 and offers both an average ROM for each category and the expected range of cancer risk. Estimated final ROM after excluding "Noninvasive Follicular Thyroid Neoplasm with Papillary Like Nuclear Features (NIFTP)" for each of six categories has been updated based on the reported mean decreases in the ROM if excluding NIFTP. For atypia of undetermined significance (AUS) category, the subcategorization is simplified and more formalized into 2 subgroups, AUS-nuclear atypia or AUS-other, based on the implied ROM and molecular profiling. For the pediatric thyroid disease, pediatric ROMs and management algorithms are newly added for the same six reporting categories for this age group. New or revised disease nomenclatures including high-grade follicular-derived carcinoma has been updated according to the recently published 2022 World Health Organization Classification of Thyroid Neoplasms. Brand new two chapters are added including clinical perspectives and imaging studies (Chap. 13) and the use of molecular and other ancillary tests (Chap. 14). The atlas is updated with new images to illustrate more effectively for new disease entity and diagnostic criteria.