• 한국해양공학회지
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• 제32권4호
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• pp.222-227
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• 2018

Most underwater acoustic arrays for low frequency operation are deployed vertically, but a mid-range frequency horizontal array system is being developed by the Korea Research Institute of Ships and Ocean Engineering (KRISO). The horizontal array platform is deployed underwater and kept in place by weather vaning mooring. This is essential because it is nearly impossible to keep a submerged body at a given position in the water without any external force. Hence, the horizontal array platform can maintain the desired position in the presence of a weak tidal current. The objective of this study is to design an underwater platform that can maintain its horizontal position in a weak current. First, the authors investigated various virtual models, selected one of the models, and performed a small model test of the selected model at a basin. We calculated the external forces associated with the 2D motion, and then we conducted a large basin test followed by a circulation water channel test for the manufactured array platform. The results of the simplified 2D motion calculation essentially matched the results of the underwater test.

• Structural Engineering and Mechanics
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• 제75권5호
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• pp.559-569
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• 2020

In the present study, the fracture toughness of U-shaped notches made of aluminum alloy Al7075-T6 under combined tension/out-of-plane shear loading conditions (mixed mode I/III) is studied by theoretical and experimental methods. In the experimental part, U-notched test samples are loaded using a previously developed fixture under mixed mode I/III loading and their load-carrying capacity (LCC) is measured. Then, due to the presence of considerable plasticity in the notch vicinity at crack initiation instance, using the Equivalent Material Concept (EMC) and with the help of the point stress (PS) and mean stress (MS) brittle failure criteria, the LCC of the tested samples is predicted theoretically. The EMC equates a ductile material with a virtual brittle material in order to avoid performing elastic-plastic analysis. Because of the very good match between the EMC-PS and EMC-MS combined criteria with the experimental results, the use of the combination of the criteria with EMC is recommended for designing U-notched aluminum plates in engineering structures. Meanwhile, because of nearly the same accuracy of the two criteria and the simplicity of the PS criterion relations, the use of EMC-PS failure model in design of notched Al7075-T6 components is superior to the EMC-MS criterion.

• 한국게임학회 논문지
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• 제14권2호
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• pp.77-84
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• 2014

면광원에 의한 부드러운 그림자의 표현은 가상 장면을 보다 사실적으로 보이도록 한다. 하지만 부드러운 그림자의 계산은 매우 느리게 수행되기 때문에 실시간 3차원 응용 프로그램에 적용하기 위해서는 가속화가 요구된다. 우리는 기존의 실시간 부드러운 그림자 방법들이 가정했던 면광원의 모양과 색상을 보다 일반적으로 확장하여 임의의 모양과 색상을 갖는 면광원에 대한 부드러운 그림자 생성 방법을 제안한다. 그림자 매핑 정보를 획득할 수 있는 그림자 맵은 픽셀과 면광원 간의 가시성 검사를 근사하기 위해 사용되며 픽셀 주변의 그림자 복잡도에 따라 근사의 정도를 결정하였다. 그 결과 보다 일반적인 형태와 색상의 면광원에 대한 부드러운 그림자를 실시간에 표현할 수 있었다.

• Advances in nano research
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• 제7권6호
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• pp.379-390
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• 2019

Putting emphasis on the effect of existence of porosity in the functionally graded materials (FGMs) on the dynamic responses of waves scattered in FG nanobeams resulted in implementation of a novel porosity-based homogenization method for FGMs and show its applicability in a wave propagation problem in the presence of axial pre-load for the first time. In the employed porosity-dependent method, the coupling between density and Young's moduli is included to consider for the effective moduli of the FG nanobeam by the means of a more reliable homogenization technique. The beam-type element will be modeled via the classical theory of beams, namely Euler-Bernoulli beam theory. Also, the dynamic form of the principle of virtual work will be extended for such nanobeams to derive the motion equations. Applying the nonlocal constitutive equations of Eringen on the obtained motion equations will be resulted in derivation of the nanobeam's governing equations. Depicted results reveal that the dispersion responses of FG nanobeams will be decreased as the porosity volume fraction is increased which must be noticed by the designers of advanced nanosize devices who are interested in employment of wave dispersion approach in continuous systems for specific goals.

• 한국의류산업학회지
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• 제21권4호
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• pp.401-411
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• 2019

Non-contact judgment and evaluation for products are increasingly needed along with a rapid environmental change in fashion that sows urgency in the need to implement services that allows users to judge and experience a tactile sense in a fashion product without actual contact. Technological development is required to provide users with syn-aesthetic experiences that integrate the visual, tactile and the auditory. There is also a need to conduct research to increase immersion that provides users with ICT-related experiences communicated through fashion images. The study analyzed demands for haptic communication technology by Korean users in immersive VR fashion product shopping. Accordingly, it defined haptic communication through literature research, investigated immersion in the VR environment and conducted in-depth interviews for haptic communication applicable to VR shopping. Findings show that hedonic reactions by fantasy, emotion and fun function are an important motive in selecting VR shopping. VR fashion product shopping steps were divided into 4: move to store, search in store, search of product and purchase based on offline store shopping experience. It defined the haptic communication by steps and analyzed the types of the haptic feedback to be implemented. The study results provide basic data for developing haptic communication technology that can enhance e a sense of the presence and immersion experiences that can help lay a groundwork for pilot studies on the convergence of the virtual and the real.

• 드라이브 ㆍ 컨트롤
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• 제19권3호
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• pp.23-31
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• 2022

Traffic safety issues have recently been seriously magnified, due to child deaths in apartment complexes and parking lots. Accordingly, traffic safety technologies are being developed to recognize dangerous situations on living roads and to provide warning services. In this study, a collision detection algorithm was developed to prevent collision accidents between moving objects, by using object type and location information provided from CCTV monitoring devices. To determine the exact collision between moving objects, an object movement model was developed to predict the range of movement by considering the moving characteristics of the object, and a collision detection algorithm was developed to efficiently analyze the presence and location of the collision. The developed object movement model as well as the collision detection algorithm were simulated, in a virtual space of an actual living road to verify performance and derive supplementary matters.

• 수완나부미
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• 제15권2호
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• pp.23-55
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• 2023

Just as globalization has many aspects and has developed in various, sometimes contradictory ways with both positive and negative impacts, so too would the reverse process of deglobalization have wide-ranging effects for individuals, communities, and nations. Some parts of globalization began to fray during the coronavirus pandemic (e.g. failing supply chains and disarray in the global shipping industry). Deglobalization would bring about much more significant changes in focusing on local production and consumption, eschewing non-essential flights and international tourism, and replacing personal experience with virtual presence. These impacts would be particularly severe for Vietnam, since its government has placed intensive connectivity with global production at the center of its model for the rapid development on which much of its legitimacy rests and it has joined as many international, multilateral organizations, and protocols as it has been able to do. Through critical analysis of secondary data from a wide range of sources, this paper examines the motivations that people, institutions, and governments might have to pursue deglobalization and then seeks evidence for whether the changes that would bring have started to affect Vietnam. While it is difficult to be too certain about this while the pandemic continues, it is evident that pressures are building in the global north to reconfigure supply chains for greater security, to reduce carbon emissions through regulating long-distance exchanges, and to withdraw from personal contacts. It is argued that a focus on digitalization in economy and society will help to mitigate the negative effects of deglobalization on Vietnam, at least in the medium-term.

• Asia pacific journal of information systems
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• 제30권1호
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• pp.21-30
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• 2020

Bitcoin (BTC) is a type of cryptocurrency that supports transaction/payment of virtual money between BTC users without the presence of a central authority or any third party like bank. It uses some cryptographic techniques namely public- and private-keys, digital signature and cryptographic-hash functions, and they are used for making secure transactions and maintaining distributed public ledger called blockchain. In BTC system, each transaction signed by sender is broadcasted over the P2P (Peer-to-Peer) Bitcoin network and a set of such transactions collected over a period is hashed together with the previous block/other values to form a block known as candidate block, where the first block known as genesis-block was created independently. Before a candidate block to be the part of existing blockchain (chaining of blocks), a computation-intensive hard problem needs to be solved. A number of miners try to solve it and a winner earns some BTCs as inspiration. The miners have high computing and hardware resources, and they play key roles in BTC for blockchain formation. This paper mainly analyses the underlying cryptographic techniques, identifies some weaknesses and proposes their enhancements. For these, two modifications of BTC are suggested ― (i) All BTC users must use digital certificates for their authentication and (ii) Winning miner must give signature on the compressed data of a block for authentication of public blocks/blockchain.

• 한국터널지하공간학회 논문집
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• 제22권4호
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• pp.337-346
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• 2020

도심권의 교통 집중과 정체로 인하여 지하 공간 활용성이 필요함에 따라 지하구조물에 대한 연구가 늘어나고 있다. 그 중 복층터널은 지하구조물을 대표 할 수 있다. 복층터널은 중간슬래브를 기준으로 상, 하부 차도를 구분하여 운영하고 있다. 중간슬래브는 차량의 하중 및 지진하중에 의하여 동적거동을 한다. 특히 지진의 의한 응답특성은 하중의 크기 및 작용 메커니즘이 매우 복잡하고 이론적 접근이 어려워 실험적 연구가 필요하다. 본 연구에서는 붕괴방지 내진 1등급의 복층터널 중간슬래브에 진동 감쇠 고무받침 유무에 따른 안정성 평가를 실시하는데 목적을 두고 있다. 본 진동대 실험에서는 상사율 1/4을 적용하였으며, 모형실험에서 지반과 모형의 일체거동을 묘사하기 위하여 라이닝과 진동대판을 고정시켰으며 이를 통해서 상대거동을 최소화 하였다. 실험대상은 가상복층터널 TBM 표준단면으로 정했다. 기반암에 가해지는 지반운동 수준을 0.154 g (붕괴방지 수준 내진 1등급 인공지진파)이며 이 가속도를 최대로 하는 지진파를 진동대 입력(기반암)에 작용시켜 모형에 증폭현상을 분석하고 진동 감쇠 고무받침 유무에 따른 중간슬래브의 내진 안정성에 대해 평가 분석 하였다. 그 결과, 지진 감쇠 고무받침 유무에 따라서 지진 가속도 감쇠 효과가 최대 40% 이상 있음을 알 수 있었다.

• 만화애니메이션 연구
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• 통권42호
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• pp.177-194
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• 2016

본 연구는 인 게임 애니메이션의 진화과정을 탐구하고 가상현실을 구축하는 실재화의 작용을 연구하였다. 인 게임 애니메이션은 게임을 가시화시켜주는 콘텐츠로 게임의 목표를 달성하기 위한 정보를 전달하는 역할을 담당하고 있다. 이러한 인 게임 애니메이션은 컴퓨터 그래픽 기술에 영향을 받아 점과 선으로 지표를 설정하는 것에서 시작하였으나 기술이 발달함에 따라 아이콘화, 구체화, 입체화의 과정을 거치며 발전하였고 오늘날 인 게임 애니메이션은 실재화를 추구하기에 이르렀다. 실재화는 시각적 촉각성에 의한 것으로 시각으로 정보를 전달받는 과정에서 사실과 같은 감각을 전달하거나 시각정보에 의해 새로운 감각을 전달받게 되는 것이다. 인 게임 애니메이션의 실재화는 시각적 촉각성에 의해 현전감을 형성하며 몰입의 경험을 제공하는데서 매우 중요하다. 때문에 인 게임 애니메이션의 이미지는 단순히 현실 세계에 대한 모방이 아니라 가상성의 전제하에 스토리에 따라 캐릭터와 배경 등의 요소를 통해 공간을 구축하여 실재의 의미를 형성하게 한다. 의미 형성 과정은 게이머에게 경험을 제공하고, 시각적 인지를 통해 감각을 확장시켜, 가상을 실재와 같이 받아들이도록 하는 것이다. 또한 경험의 만족을 위해 다양한 볼거리를 제공하는데 환상과 환영에의 한 스펙터클로 게이머의 상상력에 영향을 미치며 이미지를 통한 강력한 몰입작용을 느끼게 된다. 이처럼 인 게임 애니메이션이 추구하는 실재화의 과정은 단순히 기술발달에 따른 것이 아니라 게임으로 몰입하기 위한 작용이다. 따라서 인 게임 애니메이션은 게임의 특성에 맞추어 이미지를 구축하고 있으며 그렇기 위해 게임이 추구하는 가상적 세계에 맞는 다양한 요소가 조화를 이루며 실재화를 이루고 있다. 정리하자면, 인 게임 애니메이션의 실재화는 무조건으로 사실적인 이미지를 묘사하는 것만 추구하는 것이 아니라 게임의 장르와 스토리, 게임의 세계관 등에 따라 새로운 세계를 형성하는데 집중하는 것이며 게이머의 상상력을 자극하여 게임으로 몰입하게 하기 위한 기능을 극대화하기 위한 중요한 장치라고 볼 수 있다.