• International Journal of Aeronautical and Space Sciences
• /
• 제8권2호
• /
• pp.107-120
• /
• 2007

Coordination of multiple UAVs is an essential technology for various applications in robotics, automation, and artificial intelligence. In general, it includes 1) waypoints assignment and 2) trajectory generation. In this paper, we propose a new method for this problem. First, we modify the concept of the standard visibility graph to greatly improve the optimality of the generated trajectories and reduce the computational complexity. Second, we propose an efficient stochastic approach using simulated annealing that assigns waypoints to each UAV from the constructed visibility graph. Third, we describe a method to detect collision between two UAVs. FinallY, we suggest an efficient method of controlling the velocity of UAVs using A* algorithm in order to avoid inter-UAV collision. We present simulation results from various environments that verify the effectiveness of our approach.

• 전기학회논문지
• /
• 제63권8호
• /
• pp.1140-1145
• /
• 2014

Tunnel lighting is composed of entrance zone, interior zone and exit zone by KS C 3703. We have to consider adaptation at entrance zone and exit zone lighting to prevent deteriorate visibility like black hole and white hole phenomenon. So External luminance, vehicle velocity and traffic volume should be considered in threshold zone lighting and vehicle speed and traffic volume should be considered in interior zone lighting. But existing tunnel lighting system is not good at visibility and economic because that is only controled by external luminance. So in this paper, We improve visibility and economic of tunnel lighting system using fuzzy reasoning according to external luminance, vehicle velocity, traffic volume.

• 한국대기환경학회지
• /
• 제31권4호
• /
• pp.319-329
• /
• 2015

The characteristics of aerosol light extinction were investigated by comparing measured and calculated extinction coefficient to understand the contribution of air pollutants on visibility impairment for data during 4 months (Jan~ April), 2014. The integrated nephelometer and aethalometer system were installed to measure the scattering and absorption coefficients of aerosol as well as BAM 1020, MARGA, semi-continuous OCEC analyzer, and online-XRF to calculate the extinction coefficient. The IMPROVE_2005 equation was used to determine the contributions of different chemical components on visibility impairment in $PM_{2.5}$ and $PM_{10}$ due to highest correlation with measured data. Sulfate, nitrate, and organic mass by carbon (OMC) of fine aerosol were the major contributors affecting on visibility impairment. Total contributions to light extinction were calculated as $631.0Mm^{-1}$ for the worst-case and $64.4Mm^{-1}$ for the best-case. The concentrations of aerosol component for the worst-case were 38.4 times and 45.5 times larger than those of the best-case for $(NH_4)_2SO_4$ and $NH_4NO_3$, respectively. At lower visibility condition, in which extinction coefficient was higher than $400Mm^{-1}$, extinction coefficient varied according to the relative humidity variation regardless of $PM_{2.5}$.

• 한국의류산업학회지
• /
• 제25권4호
• /
• pp.520-533
• /
• 2023

The present study developed a test protocol for evaluating the mobility of firefighting chemical and flame personal protective equipment (PPE) for the National 119 Rescue Headquarters in Korea and suggested ergonomic design factors to improve their mobility and performance. Six types of PPE were employed, including three types for flame protective PPE (5 ~ 6 kg excluding the self-contained breathing apparatus), and three types for chemical and flame protective PPE (8 ~ 11 kg). These PPEs are used by the 119 Rescue firefighters. Three male firefighters (34.3 ± 1.2 y in age, 175 ± 8 cm in height, 81 ± 13 kg in body weight) participated in the mobility test and interview. A mobility test protocol consisting of 16 components (nine postures and seven motions including a dexterity test) along with a visibility test were developed based on pre-interviews and literature reviews. The findings indicated that the clothing microclimate humidity on the neck and chest exceeded 85%RH on average for all the six PPE conditions, with the chest area reaching as high as 98%RH. This high humidity caused fogging inside the visor and impaired visibility. The requirements for improving the PPE design in terms of mobility varied depending on whether it was the separated types or all-in-one types, particularly regarding the hood and gloves design. The findings of this study can be applied to improve the design of Level A_PPE for firefighters. The mobility test protocol and visibility test developed in this study can also be applied to other types of Level A impermeable PPE.

• International Journal of Knowledge Content Development & Technology
• /
• 제9권4호
• /
• pp.47-68
• /
• 2019

The study investigates the utilization of open access repositories for visibility of academic publications by lecturers in South-East, Nigeria. The specific objectives were to investigate the types of academic publications available, platforms used in self-archiving, level of satisfaction derived by lecturers with the contribution of open access repositories, challenges and strategies. It adopted descriptive survey design. Proportionate stratified sampling technique was used to draw a sample size of 418 from the total population of 4,187 lecturers. Questionnaire and observation check list were used for data collection. Frequency count, percentage, and mean score were used to analyze the data. The study revealed that there are enough academic publications available such as books, journals, projects, and thesis with the exception of handouts. It also revealed that Google Scholar, Research Gate and Open Access Journal were the main platforms lecturers use in self-archiving; while other platforms like Institutional Repositories, among others were minimally employed. Lecturers are less satisfied with the contribution of open access repositories. All the suggested challenges such as inadequate power supply, poor network, lack of awareness and inadequate research grants were all accepted. Similarly, all the suggested strategies for improving them were accepted. Recommendations were made based on the findings such as more awareness creation on importance of open access repositories; re-training of lecturers and provision of adequate ICT infrastructures that will improve the utilization of open access repositories by lecturers which could enhance the global visibility of academic publications from the Nigerian Universities.

• 디지털산업정보학회논문지
• /
• 제10권1호
• /
• pp.181-193
• /
• 2014

The environment of supply chains is rapidly changed to global and eco-freindly work process. However, at current environment, it is not easy to grasp work flow and to analyze energy efficiency. Improving energy efficiency and visibility for goods flow can contribute to increases in customer attitudes and reductions in overall production costs Additionally, it can lead to increases in work efficiency and reductions in overall production costs. Until recently, efforts to improve energy performance focused on manufacturing industry. Those efforts have expanded to the supply chain. In this paper, we perform business process modeling about supply chain for visibility and sustainability - information and component flows - from assembly plants to logistics. This paper defines the work and information flows by modeling the underlying logical structures of the supply chain and the business processes that determine impact of visibility and sustainability. We model processes using the modeling methodology specified by UN/CEFACT. This methodology explains business process functionality and business transactions by UML diagram. The output of this paper would be useful in grasping work flow and capturing the used energy.

• 한국광학회지
• /
• 제14권6호
• /
• pp.643-648
• /
• 2003

위상편이 회절격자 간섭계의 회절격자는 간섭을 일으키는 측정광과 기준광을 분할하고, 재결합하여 간섭무늬를 생성하고, 또한 위상을 편이시키는 다양한 용도로 사용되는 핵심부품이다. 위상편이 회절격자 간섭계는 회절격자에서 회절되는 다양한 회절차수의 광들을 측정광과 기준광으로 선정하고 서로 간섭시켜 간섭무의를 얻을 수 있는데, 그 회절차수와 사용하는 회절격자의 형상에 따라서 측정광과 기준광의 효율이 달라져서 간섭무늬의 가시도가 달라진다. 본 논문에서는 두 가지 위상편이 회절격자 간섭계에서 측정광과 기준광의 상대적인 효율을 격자에서 일어나는 회절현상의 전자기학적인 수치모사를 통해 산출해내어 각 간섭계에 최적인 회절격자의 형상을 선정한다.

• Journal of Information Science Theory and Practice
• /
• 제2권2호
• /
• pp.16-32
• /
• 2014

As Topic Modeling has been applied in increasingly various domains, the difficulty in naming and characterizing topics also has been recognized more. This study, therefore, explores an approach of combining text mining with network analysis in a multi-step approach. The concept of synchronization was applied to re-assign the top author keywords in more than one topic category, in order to improve the visibility of the topic-author keyword network, and to increase the topical cohesion in each topic. The suggested approach was applied using 16,548 articles with 2,881 unique author keywords in construction and building engineering indexed by KSCI. As a result, it was revealed that the combined approach could improve both the visibility of the topic-author keyword map and topical cohesion in most of the detected topic categories. There should be more cases of applying the approach in various domains for generalization and advancement of the approach. Also, more sophisticated evaluation methods should also be necessary to develop the suggested approach.

• 방송공학회논문지
• /
• 제27권5호
• /
• pp.812-815
• /
• 2022

햇빛 아래에서 디지털 기기에 표시되는 영상은 일반적으로 원본 영상보다 어둡게 인식되어 시인성이 저하된다. 더 나은 시인성을 위해서, 주변광에 적응적인 전역 휘도 보상 혹은 톤 매핑이 필요하다. 하지만 기존의 기법들은 색차 보상에 한계가 존재하고, 무거운 계산 비용 때문에 실제 환경에서 활용하는데 어려움이 존재한다. 이를 해결하기 위해 본 논문에서는 휘도와 색차를 모두 보상하는 Piece-wise Linear Enhancement Curves (PLECs) 기반 영상 개선 기법을 제안한다. 이때, PLECs은 딥러닝을 통해 회귀 되며, lookup table 형식으로 구현되어 실시간 동작이 가능하다. 실험 결과 제안 방법이 낮은 계산 비용으로 원본 영상 대비 더 나은 시인성을 가짐을 보인다

• 감성과학
• /
• 제20권2호
• /
• pp.137-148
• /
• 2017

본 연구는 일련의 문자열들 중 하나의 표적을 탐지하는 데 자극 명암대비와 색상이 미치는 영향을 관찰하였다. 실험 1의 각 시행에서는 네 문자로 구성된 RSVP가 제시되고 각 RSVP 화면상의 문자들이 서로 다른 위치를 점유하였다. RSVP 배열 내에서는 한 위치에 회색 표적 문자가, 나머지 위치에 세 방해자극들이 제시된 표적화면을 제외하고 나머지 RSVP 화면에서 네 흰색 방해자극 문자들이 상응하는 위치에 제시되었다. 고가시성 조건에서는 회색 배경화면 보다 표적 회색이 현저히 어두웠던 반면 저가시성 조건에서는 그 밝기 차이가 상대적으로 분명치 않았다. 참가자들은 사전에 지정된 표적들 중 각 시행에서 어느 것이 출현했는지를 가능한 빠르고 정확하게 탐지하도록 요구받았으며 그 결과 관찰된 탐지 수행은 고가시성 조건에서 더 정확했으며 신속했다. 실험 2에서는 고가시성 조건의 회색 표적을 고선명도 유채색 표적으로 대체한 것을 제외하고 실험 1과 동일한 RSVP 화면 및 과제가 사용되었다. 그 결과 참가자들은 고가시성 조건의 표적을 더 정확히 탐지했으나 반응 속도에 있어서는 두 가시성 조건 간 차이가 없었다. 두 실험의 결과는 시각적 부담이 높은 상황일지라도 현저한 명암대비 및 색상이 부여될 경우 자극에 대한 지각이 촉진됨을 시사하며 자극 색상에 비해 명암대비가 지각적 촉진에 더 중요한 역할을 수행할 가능성을 제안한다.