• 해양환경안전학회지
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• 제29권3호
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• pp.281-287
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• 2023

Establishing a ship's passage plan is an essential step before it starts to sail. The research related to the automatic generation of ship passage plans is attracting attention because of the development of maritime autonomous surface ships. In coastal water navigation, the land, islands, and navigation rules need to be considered. From the path planning algorithm's perspective, a ship's passage planning is a global path-planning problem. Because conventional global path-planning methods such as Dijkstra and A^* are time-consuming owing to the processes such as environmental modeling, it is difficult to modify a ship's passage plan during a voyage. Therefore, the D^* algorithm was used to address these problems. The starting point was near Busan New Port, and the destination was Ulsan Port. The navigable area was designated based on a combination of the ship trajectory data and grid in the target area. The initial path plan generated using the D^* algorithm was analyzed with 33 waypoints and a total distance of 113.946 km. The final path plan was simplified using the Douglas-Peucker algorithm. It was analyzed with a total distance of 110.156 km and 10 waypoints. This is approximately 3.05% less than the total distance of the initial passage plan of the ship. This study demonstrated the feasibility of automatically generating a path plan in coastal navigation for maritime autonomous surface ships using the D^* algorithm. Using the shortest distance-based path planning algorithm, the ship's fuel consumption and sailing time can be minimized.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제17권5호
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• pp.1339-1355
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• 2023

Localization is a hot research spot for many areas, especially in the mobile robot field. Due to the weak signal of the global positioning system (GPS), the alternative schemes in an indoor environment include wireless signal transmitting and receiving solutions, laser rangefinder to build a map followed by a re-localization stage and visual positioning methods, etc. Among all wireless signal positioning techniques, Wi-Fi is the most common one. Wi-Fi access points are installed in most indoor areas of human activities, and smart devices equipped with Wi-Fi modules can be seen everywhere. However, the localization of a mobile robot using a Wi-Fi scheme usually lacks orientation information. Besides, the distance error is large because of indoor signal interference. Another research direction that mainly refers to laser sensors is to actively detect the environment and achieve positioning. An occupancy grid map is built by using the simultaneous localization and mapping (SLAM) method when the mobile robot enters the indoor environment for the first time. When the robot enters the environment again, it can localize itself according to the known map. Nevertheless, this scheme only works effectively based on the prerequisite that those areas have salient geometrical features. If the areas have similar scanning structures, such as a long corridor or similar rooms, the traditional methods always fail. To address the weakness of the above two methods, this work proposes a coarse-to-fine paradigm and an improved localization algorithm that utilizes Wi-Fi to assist the robot localization in a geometrically similar environment. Firstly, a grid map is built by using laser SLAM. Secondly, a fingerprint database is built in the offline phase. Then, the RSSI values are achieved in the localization stage to get a coarse localization. Finally, an improved particle filter method based on the Wi-Fi signal values is proposed to realize a fine localization. Experimental results show that our approach is effective and robust for both global localization and the kidnapped robot problem. The localization success rate reaches 97.33%, while the traditional method always fails.

• 한국방송∙미디어공학회:학술대회논문집
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• 한국방송∙미디어공학회 2022년도 하계학술대회
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• pp.205-208
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• 2022

Multi-exposure high dynamic range (HDR) image reconstruction, the task of reconstructing an HDR image from multiple low dynamic range (LDR) images in a dynamic scene, often produces ghosting artifacts caused by camera motion and moving objects and also cannot deal with washed-out regions due to over or under-exposures. While there has been many deep-learning-based methods with motion estimation to alleviate these problems, they still have limitations for severely moving scenes. They also require large parameter counts, especially in the case of state-of-the-art methods that employ attention modules. To address these issues, we propose a frequency domain approach based on the idea that the transform domain coefficients inherently involve the global information from whole image pixels to cope with large motions. Specifically we adopt Residual Fast Fourier Transform (RFFT) blocks, which allows for global interactions of pixels. Moreover, we also employ Depthwise Overparametrized convolution (DO-conv) blocks, a convolution in which each input channel is convolved with its own 2D kernel, for faster convergence and performance gains. We call this LFFNet (Lightweight Frequency Fusion Network), and experiments on the benchmarks show reduced ghosting artifacts and improved performance up to 0.6dB tonemapped PSNR compared to recent state-of-the-art methods. Our architecture also requires fewer parameters and converges faster in training.

• 무역학회지
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• 제48권4호
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• pp.169-188
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• 2023

공세적이고 일방주의적 조치의 증가는 최근 국제통상환경의 대표적인 특징이다. EU는 이러한 환경에 대처하기 위해 제3국의 경제적 위협 시 독자적인 대응조치 허용을 골자로 하는 '경제적 위협 대응조치 규칙안' 도입을 추진하고 있다. 본 고는 규칙안의 입법 배경인 최근 공세적 통상환경의 특징을 살펴보고 기존 EU의 통상정책과의 연계 및 발전 맥락에서 동 규칙안의 필요성 및 우려의 측면을 평가하였다. 또한 타국의 경제적 위협에 대해 독자적으로 대처하고자 하는 시도가 국제적으로 확산되고 있는바, EU의 경제적 위협 대응조치 규칙안의 WTO 체제하에서의 허용 가능성을 검토하였다. 마지막으로 점증하는 지정학적 위기 속에서 우려되는 경제적 위협과 통상마찰에 대한 우리의 국내적 대응 방안 측면에서 동 규칙안의 시사점을 도출하였다.

• 문화기술의 융합
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• 제10권3호
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• pp.559-564
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• 2024

산업혁명 이래 쓰레기 배출은 증가해 왔으며 폐기물의 처리 문제는 오늘날 인류가 직면한 가장 대표적 환경문제 중 하나가 되었다. 그러나 쓰레기는 님비 운동을 촉발하는 등, 처리 문제를 둘러싸고 다양한 국가, 정부 및 사회 주체들 간의 갈등은 고조되고 있다. 국가와 지방정부 수준에서 쓰레기 문제의 처리 방식으로는 제도, 법, 규제, 시장적 접근법, 합의와 협력적 거버넌스 등 다양한 방안이 도입, 적용되어 왔다. 최근에는 순환 경제라는 개념 하에 과학 기술을 적용하여 폐기물을 재활용, 재자원화하는 등의 방안도 주목받고 있다. 그러나 쓰레기 문제 해결을 위한 사회적 지지는 여전히 불충분하며 이에 새로운 접근법과 대안 모색이 필요한 시점이다. 본 논문은 훈데르트바서라는 예술가가 설계한 오스트리아 수도 빈의 슈피텔라우 소각장과 일본 오사카의 마이시마 소각장을 사례연구(case study) 하였다. 이들 사례는 오스트리아 출신의 훈데르트바서가 예술과 기술의 창의적, 혁신적 융합을 통해 어떻게 폐기물과 같은 도시 환경문제이자 공공의 문제에 대한 새로운 대안과 접근법을 제시하였는지 보여준다. 이들 사례는 오늘날의 환경문제 해결에 있어 과학기술적. 경제적 접근법과 더불어 예술과 문화의 융합이 유용할 수 있음을 시사한다.

• Architectural research
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• 제18권1호
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• pp.21-29
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• 2016

Importance of FM has rapidly increased because of its growing business. However, due to lack of clarity and identity of FM in professional areas, standardization of FM became to be imperative in such a rapidly changing global business environment. Facility services are defined as the provision of support the primary activities of an organization, delivered by an internal or external provider. Majority of FM activities are services related to 'space and infrastructure' and 'people and organization' (CEN, 2011). The purpose of this study is to investigate definitions and characteristics of FM from both globally and domestic environment, by comparison with international or national standards, to identify quality management in FM and service characteristics of FM, to investigate the differences in service level elaboration in FM, and to suggest standard issues of quality management in FM service quality. This study examines contents of the European Standards in FM, Part 3 'Guidance on quality in Facility Management, especially for the process of QM standardized by CEN (2011) and explores undefined issues such as service level, measurement metrics according to service characteristics of FM. The European FM Standard guides the common process of QM in terms of requirements specification, service level elaboration, measurement metrics development although it does not specifically address various service levels, specific performance metrics and indicators.

• Architectural research
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• 제12권2호
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• pp.63-72
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• 2010

Affordable housing has been a critical issue in the face of global economy and notably formulated a crucial agenda of the housing policy. While each local government seriously considers many approaches to providing affordable housing, a unique and innovative way to address it at a community level is fully uncovered, particularly nonmetropolitan areas where resources for economic development are limited and vulnerable. The purpose of this study is to examine the mechanism of the provision of affordable housing for the elderly in nonmetropolitan areas. In doing so, this research investigates the housing development and delineates it as one viable solution that stimulates local communities. The affordable housing development, as a viable option to spur local development and vibrate community, is closely reviewed, and the factors to make it feasible are drawn. The findings indicate that it is widely recognized that keeping the elderly in the community positively contributes to maintaining a sustainable community. In fact, the idea of affordable housing development for middle-class elderly people is brought by one inspired long-time resident, and it is expedited by the consensus and cohesion of local community. The development stimulates local businesses in relation to housing, and all homes sold by the elderly moving in the new housing are available for young families. Also, the presence of affordable housing for the elderly who are able to independently live is extended to a picture of aging-in-place at a broader level.

• Journal of Communications and Networks
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• 제16권1호
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• pp.18-25
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• 2014

In this paper, we propose a codebook-based interference alignment (IA) scheme in the constant multiple-input multiple-output (MIMO) interference channel especially for the uplink scenario. In our proposed scheme, we assume cooperation among base stations (BSs) through reliable backhaul links so that global channel knowledge is available for all BSs, which enables BS to compute he transmit precoder and inform its quantized index to the associated user via limited rate feedback link. We present an upper bound on the rate loss of the proposed scheme and derive the scaling law of the feedback load to maintain a constant rate loss relative to IA with perfect channel knowledge. Considering the impact of overhead due to training, cooperation, and feedback, we address the effective degrees of freedom (DOF) of the proposed scheme and derive the maximization of the effective DOF. From simulation results, we verify our analysis on the scaling law to preserve the multiplexing gain and confirm that the proposed scheme is more effective than the conventional IA scheme in terms of the effective DOF.

• 한국산업정보학회논문지
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• 제22권3호
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• pp.27-38
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• 2017

본 연구는 다수의 개인 사용자들이 휴대폰 카메라를 통하여 공연장 등에서 녹화한 다수의 영상을 스티칭하는 방법을 제시한다. 기존 고정형 리그(Rig)를 사용하는 360 카메라 솔루션과 대비하여, 시간 동기화, 반복적 변환행렬계산 및 카메라 센서 불일치 보정과 같은 새로운 문제들을 해결해야한다. 이 논문에서는 오디오를 사용한 시각동기화 방법, 색상 전달 방식에 따른 센서 불일치 제거, 전역 동작 안정화 알고리즘을 사용하여 변환 행렬의 업데이트를 함으로써 이러한 문제를 해결하였다. 또한, 카메라의 움직임이 크지 않은 경우에서, 제안 된 알고리즘은 화면 별 스티칭을 하는 경우 보다, 계산 속도와 화질 면에서도 우수한 성능을 보임을 실험을 통하여 확인하였다.

• Journal of Computing Science and Engineering
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• 제11권2호
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• pp.49-57
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• 2017

This paper proposes a new IPv6 networking paradigm as a counter answer to the rationale for locator/identifier separation. Instead of involving separate number spaces each for node identifiers and locators, the context of the IP address as a node identifier alone is utilized and no additional locators are incorporated. That is, there are only node addresses and no locators, and location information is indirectly derived from neighbor relations between nodes. In order to accomplish this, no subnet IDs are utilized; the ID value is set to zero for all subnets. The paper details how to construct this paradigm through novel choice of operational policies in various IPv6 protocols and some trivial modifications. Especially, inherent provision of intra-domain node- as well as subnet-mobility by use of standard link-state intra-domain routing protocols is discussed. A number of important advantages of this paradigm over the canonical IPv6 networking and various known solutions of locator/identifier separation are discussed. Tailoring for multi-area domains and IPv4 is left for further study.