• International Journal of Internet, Broadcasting and Communication
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• 제16권2호
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• pp.237-246
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• 2024

In recent years, the frequent occurrence of fire accidents in university libraries has posed significant threats to the safety of students' lives and property, alongside negative social impacts. Accurately analyzing the factors affecting evacuation during library fires and proposing optimized measures for safe evacuation is thus crucial. This paper utilizes a specific university library as a case study, simulating fire evacuation scenarios using the Pathfinder software, to assess and validate evacuation strategies and propose relevant optimizations. Pathfinder, developed by Thunderhead Engineering in the United States, is an intuitive and straightforward personnel emergency evacuation assessment system, offering advanced visualization interfaces and 3D animation effects. This study aims to construct evacuation models and perform simulation analysis for the selected university library using Pathfinder. The library's structural layout, people flow characteristics, and the nature of fire and smoke spread are considered in the analysis. Additionally, evacuation scenarios involving different fire outbreak locations and the status of emergency exits are examined. The findings underscore the importance of effective evacuation in fire situations, highlighting how environmental conditions, individual characteristics, and behavioral patterns significantly influence evacuation efficiency. Through these investigations, the study enhances understanding and optimization of evacuation strategies in fire scenarios, thereby improving safety and efficiency. The research not only provides concrete and practical guidelines for building design, management, and emergency response planning in libraries but also offers valuable insights for the design and management of effective evacuation systems in buildings, crucial for ensuring occupant safety and minimizing loss of life in potential hazard situations

• 한국전기전자재료학회논문지
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• 제37권4호
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• pp.382-393
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• 2024

유체 디스펜싱(fluid dispensing) 방식인 Microplotter 시스템은 압전 소자를 통한 초음파 펌핑(pumpin)을 기반으로 유체를 분사한다. 이 기법은 넓은 범위의 점도를 가진 다양한 물질들이 마이크로 사이즈로 프린팅 되는 것을 가능하게 한다. 본 논문에서는 디스펜서 프린팅 기술에 대해 소개하고 장비를 이용한 다양한 공정을 이해 및 응용에 목적을 두고 있다. 또한, 분사 강도, 분사 시 팁의 높이, 분사 속도와 같은 매개변수들을 조절하여 장비의 최적화 방법에 대해 설명하고자 한다. 금속 나노 입자, 탄소나노튜브, DNA, 단백질 등 광범위한 유체와 호환된다는 Microplotter의 장점을 이용함으로써 인쇄전자, 생명공학, 화학공학 등 다양한 분야에서 활용될 것으로 기대된다.

• Ocean Systems Engineering
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• 제14권2호
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• pp.171-210
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• 2024

This paper focuses on the rigorous and holistic fatigue analysis of mooring chains for a deep draft semi-submersible platform in the challenging environment of the central Gulf of Mexico (GoM). Known for severe hurricanes and strong loop/eddy currents, this region significantly impacts offshore structures and their mooring systems, necessitating robust designs capable of withstanding extreme wind, wave and current conditions. Wave scatter and current bin diagrams are utilized to assess the probabilistic distribution of waves and currents, crucial for calculating mooring chain fatigue. The study evaluates the effects of Vortex Induced Motion (VIM), Out-of-Plane-Bending (OPB), and In-Plane-Bending (IPB) on mooring fatigue, alongside extreme single events such as 100-year hurricanes and loop/eddy currents including ramp-up and ramp-down phases, to ensure resilient mooring design. A detailed case study of a deep draft semi-submersible platform with 16 semi-taut moorings in 2,500 meters of water depth in the central GoM provides insights into the relative contributions of wave scatter diagram, VIMs from current bin diagram, the combined stresses of OPB/IPB/TT and extreme single events. By comparing these factors, the study aims to enhance understanding and optimize mooring system design for safety, reliability, and cost-effectiveness in offshore operations within the central GoM. The paper addresses a research gap by proposing a holistic approach that integrates findings from various contributions to advance current practices in mooring design. It presents a comprehensive framework for fatigue analysis and design optimization of mooring systems in the central GoM, emphasizing the critical importance of considering environmental conditions, OPB/IPB moments, and extreme single events to ensure the safety and reliability of mooring systems for offshore platforms.

• 한국구조물진단유지관리공학회 논문집
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• 제12권1호
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• pp.135-142
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• 2008

본 연구는 LB-Deck 플레이트 합성 거더교의 최적설계에 관한 것이다. LB-Deck 플레이트 합성교의 최적화에 대한 문제는 목적함수와 제약조건식으로 이루어지고, 목적함수로는 LB-Deck 플레이트 System이 포함된 콘크리트 바닥판과 강재 거더 비용의 합으로 전체비용함수를 구성하였으며, 제약조건식은 도로교 시방 규정을 기준으로 유도하였다. 최적설계에 관한 최적화 알고리즘은 SUMT기법을 사용하였으며, 지간장이 60m로 모두 같은 1경간, 2경간 및 3경간 LB-Deck 플레이트 합성 거더교와 일반적인 철근콘크리트 강재 합성교에 대하여 1등교로 최적설계하고, 이를 수치적으로 상호 비교하였다. 이렇게 함으로써 구조해석과 단면설계 및 최적설계를 동시에 수행하고, LB-Deck 플레이트의 거푸집 역할에 의한 시공성과 프리캐스트 부재에 의한 안정성 및 최적설계에 의한 경제성을 모두 확보할 수 있도록 하였다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제18권7호
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• pp.1749-1773
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• 2024

Recent advances in deep neural networks (DNNs) have greatly improved the accuracy and universality of various intelligent applications, at the expense of increasing model size and computational demand. Since the resources of end devices are often too limited to deploy a complete DNN model, offloading DNN inference tasks to cloud servers is a common approach to meet this gap. However, due to the limited bandwidth of WAN and the long distance between end devices and cloud servers, this approach may lead to significant data transmission latency. Therefore, device-edge collaborative inference has emerged as a promising paradigm to accelerate the execution of DNN inference tasks where DNN models are partitioned to be sequentially executed in both end devices and edge servers. Nevertheless, collaborative inference in heterogeneous edge environments with multiple edge servers, end devices and DNN tasks has been overlooked in previous research. To fill this gap, we investigate the optimization problem of collaborative inference in a heterogeneous system and propose a scheme CIS, i.e., collaborative inference scheme, which jointly combines DNN partition, task offloading and scheduling to reduce the average weighted inference latency. CIS decomposes the problem into three parts to achieve the optimal average weighted inference latency. In addition, we build a prototype that implements CIS and conducts extensive experiments to demonstrate the scheme's effectiveness and efficiency. Experiments show that CIS reduces 29% to 71% on the average weighted inference latency compared to the other four existing schemes.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제18권7호
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• pp.1726-1748
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• 2024

Trajectory planning is vital for autonomous systems like robotics and UAVs, as it determines optimal, safe paths considering physical limitations, environmental factors, and agent interactions. Recent advancements in trajectory planning and future location prediction stem from rapid progress in machine learning and optimization algorithms. In this paper, we proposed a novel framework for Spatial-temporal transformer-based feed-forward neural networks (STTFFNs). From the traffic flow local area point of view, skip-gram model is trained on trajectory data to generate embeddings that capture the high-level features of different trajectories. These embeddings can then be used as input to a transformer-based trajectory planning model, which can generate trajectories for new objects based on the embeddings of similar trajectories in the training data. In the next step, distant regions, we embedded feedforward network is responsible for generating the distant trajectories by taking as input a set of features that represent the object's current state and historical data. One advantage of using feedforward networks for distant trajectory planning is their ability to capture long-term dependencies in the data. In the final step of forecasting for future locations, the encoder and decoder are crucial parts of the proposed technique. Spatial destinations are encoded utilizing location-based social networks(LBSN) based on visiting semantic locations. The model has been specially trained to forecast future locations using precise longitude and latitude values. Following rigorous testing on two real-world datasets, Porto and Manhattan, it was discovered that the model outperformed a prediction accuracy of 8.7% previous state-of-the-art methods.

• 한국빅데이터학회지
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• 제8권2호
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• pp.83-95
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• 2023

스마트 플랜트 발전에 있어서 빅데이터 분석과 인공지능은 중요한 역할을 한다. 본 연구에서는 플랜트 데이터를 위한 빅데이터 플랫폼과 인공지능 기반 플랜트 유지 관리를 위한 'AutoML 플랫폼'을 개발하였다. 빅데이터 플랫폼은 하둡, 스파크, 카프카를 활용하여 플랜트에서 발생하는 대용량의 데이터를 수집, 처리, 적재하는 플랫폼이다. AutoML 플랫폼은 설비의 예지보전 및 공정 최적화를 위한 예측 모델을 구축하는 머신러닝 자동화 시스템이다. 위 플랫폼은 기존 플랜트 운영 정보 시스템과의 호환성을 고려하여 데이터 파이프라인을 구성하고, 웹 기반 GUI를 통해 작업자의 접근성과 편의성을 향상하였으며, 데이터 처리와 학습 알고리즘에 사용자 정의 모듈을 탑재하는 기능을 통해 유연성을 증대시켰다. 본 논문은 국내 정유회사의 특정 공정을 대상으로 플랫폼을 실제 운영해보았고, 이를 통해 스마트 플랜트를 위한 효과적인 데이터 활용 플랫폼 사례를 제시한다.

• 방사선산업학회지
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• 제18권3호
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• pp.155-166
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• 2024

In this study, a liquid scintillation spectrometer was developed for online continuous monitoring of tritium nuclides in water. The device consists of two photoelectron multiplier tubes (PMT), a simultaneous counting circuit, and a signal processing unit including a multi-channel analyzer (MCA). As a method to verify the performance of the equipment developed in this study, samples were prepared using a standard source, and the spectrum of tritium was measured to evaluate the detector characteristics such as efficiency, background (BKG), and minimum detectable activity (MDA). To evaluate the effect of pretreatment on tritium radioactivity measurement results, the MDA of water (seawater and groundwater) samples before and after pretreatment was calculated and compared. The results of the evaluation confirmed the satisfaction of the reference values of the Nuclear Safety Commission's "Discharge Control Standard in Drainage Water" and the World Health Organization's (WHO) "Tritium Radioactivity Concentration for Drinking Water Standards". The liquid scintillation spectrometer developed in this study, with or without pretreatment, confirmed detection performance equivalent to 1/100th of the discharge control standard for drainage water (40,000 Bq L^-1) and the WHO's drinking water standard for tritium radioactivity (10,000 Bq L^-1).

• Journal of Trauma and Injury
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• 제37권3호
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• pp.182-191
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• 2024

Purpose: Vascular injuries require immediate surgical treatment with standard vascular techniques. We aimed to identify pitfalls in vascular surgery for trauma team optimization and to suggest recommendations for trauma and vascular surgeons. Methods: We reviewed 28 victims and analyzed the patterns of injuries, methods of repair, and outcomes. Results: Ten patients had torso injuries, among whom three thoracic aorta injuries were repaired with thoracic endovascular aortic repair, one left hepatic artery pseudoaneurysm with embolization, and two inferior vena cava with venorrhaphy, three iliac arteries with patch angioplasty or embolization, and three common femoral arteries with bypass surgery or arterioplasty. Four patients had upper extremity injuries, among whom one brachial artery and vein was repaired with bypass surgery after temporary intravascular shunt perfusion, two radial arteries were repaired with anastomoses, and one ulnar artery was repaired with ligation. One radial artery under tension was occluded. Fourteen patients had lower extremity injuries, among whom one superficial femoral artery and vein was repaired with bypass and concomitant ligation of the deep femoral artery and vein, three superficial femoral arteries were repaired with bypass (two concomitant femoral veins with bypass or anastomosis), one deep femoral artery with embolization, two popliteal arteries with bypass or anastomosis, four infrapopliteal transected arteries, one arteriovenous fistula with ligation, and one pseudoaneurysm with bypass. However, one superficial femoral artery and all femoral veins were occluded. One leg replantation failed. Conclusions: There are potential complications of vascular access during resuscitative endovascular balloon occlusion of the aorta procedures. Vascular repair should be performed without tension or spasm. Preservation of the harvested vein in papaverine solution and blood while using a temporary intravascular shunt is a method of eliminating spasms.

• 국제교류와 융합교육
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• 제4권2호
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• pp.63-76
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• 2024

디지털 기술은 농촌 교육의 모습을 점차 변화시키고 전례 없는 발전 기회를 제공하고 있다. 본 연구는 디지털 기술이 농촌 교육에 미치는 영향을 분석하는 것을 목적으로 하며, 저장성 원청현을 사례로 디지털 자원의 사용 현황을 조사하고 분석하였다. 연구의 주요 초점은 농촌 교육에서 디지털 기술의 활용이 교육 균형 발전에 어떤 역할을 하는지, 그리고 이러한 기술적 발전이 직면하고 있는 주요 도전과 문제점을 밝히는 데 있다. 연구 후 원청현의 농촌 교육은 비효율적인 디지털 자원 활용, 취약한 디지털 기술 활용 능력, 불충분한 디지털 기술 혁신의 탐색과 같은 많은 문제를 가지고 있음이 밝혀졌다. 특히, 디지털 교육 자원의 중복 구매와 비효율적인 사용, 교사들의 디지털 기술에 대한 낮은 적응력 등이 주된 문제로 드러났다. 이러한 문제를 해결하기 위한 대책들이 제시되었다. 이를 통해 본 연구는 농촌 교육의 디지털화가 성공적으로 이루어지기 위한 최적화 경로를 제시하며, 다른 지역에서도 적용 가능한 정책적 시사점을 제공할 수 있을 것으로 기대된다.