• Proceedings of the Korea Information Processing Society Conference
• /
• 2018.10a
• /
• pp.939-942
• /
• 2018

최근 LED 조명을 활용한 가시광 통신(VLC: Visible Light Communications)기술이 주목을 받고 있다. 가시광 통신 기술은 Bluetooth, ZigBee 등과 함께 새로운 인터넷 접속 기술로 활용될 수 있으나 전송 용량의 한계 때문에 실제 적용이 힘든 상황이다. 본 논문에서는 이 문제를 해결하기 위해 키-값 데이터베이스 패러다임을 적용한 가시광 통신 기반의 사물인터넷(IoT: Internet of Things) 모델을 제시한다. 제안하는 IoT 환경은 플렛폼 서버, 게이트웨이, VLC 송신기 및 VLC 수신기로 구성된다. IoT 통신을 위한 각 장비의 기능 및 프로토콜 스텍을 설계하고 실험 환경에서 각 장치의 초기화 절차 및 데이터 전송 과정을 검증하였다. 실험결과, 각 장비의 초기 구동 시간을 포함하여 1분 이내에 VLC 기반의 IoT 환경 구축이 가능함을 확인하였다.

• Journal of the Korea Computer Industry Society
• /
• v.3 no.1
• /
• pp.35-44
• /
• 2002

The watchman routes which an watchman patrols the interior of given polygon moving along the route are classified to minimum length or minimum links. The watchman route with minimum links has minimum changes of direction and a weakly visible polygon consists of two chains which have mutually weakly visibility. In this paper, we present an Ο($n^2$) time algorithm for finding the watchman route with minimum links in the weakly visible polygons, where n is the number of vertices of a given polygon.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.31 no.1
• /
• pp.37-44
• /
• 1998

Feeding habits of Pseudoblennius cottoides collected from the eelgrass bed in Kwangyang Bay from January 1994 to December 1994 were studied. Pseudoblennius cottoides was a carnivore which mainly consumed fishes, caridean shrimps, and amphipods. Its diets included small Quantities of tanaids, copepods, isopods, mysids, and polychaetes. It showed ontogenetic changes in feeding habits. Fishes were heavily selected as the body size of P. cottoides increases. Fishes and caridean shrimps were major prey organisms for all seasons.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2009.05a
• /
• pp.355-359
• /
• 2009

본 논문에서는 퍼지 기법을 이용하여 구름의 종류를 분석하는 방법을 제안한다. 본 논문에서는 가시 영상과 적외 영상을 대상으로 육지 영역은 RGB 컬러 정보 중에 G 채널 값의 수치가 높고, 바다영역에서는 B 채널 값의 수치가 높다는 정보를 이용한다. 이 정보를 이용하여 육지 영역에서는 R과 B 채널 값을 적용하고, 바다 영역에서는 R과 G 채널 값을 적용한다. 가시 영상과 적외 영상에서 임계치를 적용하여 잡음(구름 이외의 영역)을 제거하고, 잡음을 제거한 영상에서 육지 영역과 바다 영역을 구분한 후, 각 R, G, B 채널 정보를 퍼지 기법에 적용하여 구름 영역을 판별한다. 그리고 가시영상과 적외 영상에 모두 포함된 구름 영역에 대해서는 두 영상을 합성하여 구름을 판별한다. 제안된 기법을 구름 분류에 적용한 결과, 제안된 방법이 기존의 양자화를 적용한 방법보다 구름의 분류 성능이 개선된 것을 확인하였다.

• 한국디지털정책학회:학술대회논문집
• /
• 2004.05a
• /
• pp.609-616
• /
• 2004

본 논문에서는 주파수 자원의 고갈로 인하여 차세대 정보통신 시스템으로 사용의 가능성이 예상되는 가시광통신의 개요와 응용기술 및 발전동향에 대하여 알아 보고자한다.

• Information and Communications Magazine
• /
• v.26 no.5
• /
• pp.15-22
• /
• 2009

본고에서는 가시광 통신에 사용되는 여러 가지 기술 특성을 간단하게 기술하고자 하였다. 광원과 감지기에 대한 기술 사항을 간단히 소개하였으며 그들의 기술 특성을 표시하는 방법에 대하여 간단히 기술하였다.

• Analytical Science and Technology
• /
• v.24 no.6
• /
• pp.493-502
• /
• 2011

The catalyst works for visible-light region was characterized. Toluene, xylene, MEK and ammonia were used as reactants. The decomposition efficiency was compared between visible-light photocatalyst and UV-light one. UV-photocatalyst can be activated with UV-light wave length of 280~360 nm. However, visible-light photocatalyst can be activated with visible wave length of 400~750 nm. This result was found by using UV-Vis absorbance. A lot of materials were doped to visible light photocatalyst in order to increase its performance. Platinum was added to visible light photocatalyst with manganese in order to increase performance of the visible light photocatalyst. MTMS (Methyl tri methoxy silane) was used as a binder. Contact angle was analyzed varying with amount of binder. Contact angle was increased with increasing the amount of MTMS. As a result, the hydrophilic property of photocatalyst with MTMS binder was decreased due to its hydrophobic one. And Mn-$TiO_2$ catalyst had an excellent anti-bacterial property.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.19 no.12
• /
• pp.2836-2843
• /
• 2015

Due to metallicity of materials, a vessel has a limitation to adopt RF-based wireless communication technologies for the inner communication means. Visible Light Communication(VLC) can be a sound alternative to dissolve such a limitation. Using a visual light as a transmission medium, VLC is free from radio interferences and restriction of radio usages which are typically related to RF-based wireless communications. In addition, VLC can not only require the facility cost relatively low because of being possibly converged with existing LED illumination, but also be harmless to the human body. This paper proposes an indoor location-based emergency call service system solution for ships using the VLC technology that supports 256Kbps data rate and 5m transmission distance. This paper presents real implementation and testing results of the solution which verifies the propriety of the proposal.

• Journal of Satellite, Information and Communications
• /
• v.7 no.3
• /
• pp.63-68
• /
• 2012

The VLC (visible light communication) system is communication technology using visible rays (RGB) that come out in LED device. It is energy curtailment effect and possible in ubiquitous network service applications. Also, VLC system has the above advantage about that the communication throughout the whole room is enabled by high power lighting and lighting equipment with white colored LED which are easy to install and have good outward appearance. However, the signal detection performance for the receiver near the network of transmitter boundary is severely degraded and the transmission efficiency decreased due to the influence of the interference signal from the adjacent networks. In this paper, we propose an interference mitigation method with optical relay and optical beamforming scheme in VLC systems, and evaluate the reception performance. For the system BER, the proposed system demonstrates the performance enhancement compared to the not using the optical relay and optical beamforming scheme, and SNR performance gain and higher channel capacity is achieved.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2018.05a
• /
• pp.668-670
• /
• 2018

Recently, VLC(Visible Light Communication), which is a technology to communicate wirelessly by carrying information in lights based on LED, is getting attention. If we use the VCL, we don't need to receive authorization because it uses the existing industrial infrastructure(LED infrastructure) and frequency band together and there is the little possibility of interference and it has a high level of security by removing visible light in a portion where data transfer is not required. These are the advantage of VCL. In this paper, we study the traffic and signal system based on Visible Light Communication with consideration for these advantages.