• KSII Transactions on Internet and Information Systems (TIIS)
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• v.16 no.1
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• pp.334-349
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• 2022

The effectiveness of Wi-Fi networks is greatly influenced by the optimization of contention window (CW) parameters. Unfortunately, the conventional approach employed by IEEE 802.11 wireless networks is not scalable enough to sustain consistent performance for the increasing number of stations. Yet, it is still the default when accessing channels for single-users of 802.11 transmissions. Recently, there has been a spike in attempts to enhance network performance using a machine learning (ML) technique known as reinforcement learning (RL). Its advantage is interacting with the surrounding environment and making decisions based on its own experience. Deep RL (DRL) uses deep neural networks (DNN) to deal with more complex environments (such as continuous state spaces or actions spaces) and to get optimum rewards. As a result, we present a new approach of CW control mechanism, which is termed as contention window threshold (CW_Threshold). It uses the DRL principle to define the threshold value and learn optimal settings under various network scenarios. We demonstrate our proposed method, known as a smart exponential-threshold-linear backoff algorithm with a deep Q-learning network (SETL-DQN). The simulation results show that our proposed SETL-DQN algorithm can effectively improve the throughput and reduce the collision rates.

• Proceedings of the Materials Research Society of Korea Conference
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• 2003.11a
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• pp.129-129
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• 2003

전기변색(electrochromism)은 전기화학적 산화, 환원 과정을 통해 가역적인 광학특성의 변화를 갖는 현상을 말하며, 이를 이용한 전기변색소자(electrochromic device)는 전력 소모가 적고 변색효율이 크다는 장점으로 인해 smart window, display, mirror 등에 응용될 수 있다. 전기변색소자는 구조상 투명 기판, 투명 전도체, 환원 착색 물질 (cathodic coloration material), 산화 착색 물질(anodic coloration material), 그리고 투명 이온 전도체로 구성된다. 일반적으로 투명 기판으로는 열적 안정성이 좋은 유리기판을 사용하여 window에 응용할 수 있는 장점이 있는 반면 다양한 형태를 갖는 소자를 제작하기에는 그 한계가 있다.

• Proceedings of the Materials Research Society of Korea Conference
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• 1994.05a
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• pp.90-90
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• 1994

• Journal of IKEEE
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• v.23 no.4
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• pp.1224-1229
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• 2019

In this study, a liquid crystal (LC) cell was manufactured for smart window applications, such as blinds, and a system for controlling the light transmission rate was developed. The threshold voltage of the LC cell was 1.325 V and when the transmission rate was 10%, the voltage showed 2.370 V, indicating that the LC cell manufactured is driven at low voltage. The LC cell also operated reliably after being heated for 10 min at 80℃. with a response time of less than 30ms. The operation system designed the applied voltage of the LC cell with a interval of about 0.5 V from 0.15 V to 3.53 V and confirmed that the light transmission rate of the LC varies depending on the actual applied voltage. These results suggest that LC cells are likely to be smart window applications.

• Journal of People, Plants, and Environment
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• v.23 no.6
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• pp.655-665
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• 2020

Background and objective: This study was conducted to compare the cultivation environment, growth of cut flowers, and management performance of conventional farms and smart farms growing the standard cut chrysanthemum, 'Jinba'. Methods: Conventional and smart farms were selected, and facility information, cultivation environment, cut flower growth, and management performance were investigated. Results: The conventional and smart farms were located in Muan, Jeollanam-do, and conventional farming involved cultivating with soil culture in a plastic greenhouse, while the smart farm was cultivating with hydroponics in a plastic greenhouse. The conventional farm did not have sensors for environmental measurement such as light intensity and temperature and pH and EC sensors for fertigation, and all systems, including roof window, side window, thermal screen, and shading curtain, were operated manually. On the other hand, the smart farm was equipped with sensors for measuring the environment and nutrient solution, and was automatically controlled. The day and night mean temperatures, relative humidity, and solar radiation in the facilities of the conventional and the smart farm were managed similarly. But in the floral differentiation stage, the floral differentiation was delayed, as the night temperature of conventional farm was managed as low as 17.7℃ which was lower than smart farm. Accordingly, the harvest of cut flowers by the conventional farm was delayed to 35 days later than that of the smart farm. Also, soil moisture and EC of the conventional farm were unnecessarily kept higher than those of the smart farm in the early growth stage, and then were maintained relatively low during the period after floral differentiation, when a lot of water and nutrients were required. Therefore, growth of cut flower, cut flower length, number of leaves, flower diameter, and weight were poorer in the conventional farm than in the smart farm. In terms of management performance, yield and sales price were 10% and 38% higher for the smart farm than for the conventional farm, respectively. Also, the net income was 2,298 thousand won more for the smart farm than for the conventional farm. Conclusion: It was suggested that the improved growth of cut flowers and high management performance of the smart farm were due to precise environment management for growth by the automatic control and sensor.

• The Journal of the Korea institute of electronic communication sciences
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• v.11 no.12
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• pp.1245-1250
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• 2016

In this study, smart laser pointer using image processing was studied. The laser pointer tracked the light by using image processing. and the tracking signal was received to the transmitting unit. Smart laser pointer received the video signal have function of erase, write convert window, and changing of font color. It was studied that the smart laser pointer system could run pointer and mouse function on the one place.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2018.11a
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• pp.145-146
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• 2018

This study was performed to develop the lifting pallets for the application of smart skin system when remodeling the balcony of apartment house. For this purpose, the smart skin system based on IoT, combining window, BIPV, ESS, air purifier applied in this study was examined. The study developed and presented a foldable double pallet considering the load (about 2Ton) and specification (width 7m × height 2.6m × width 1.3m) of the smart skin system. In future research, it is necessary to verify the application of the foldable pallet in this study.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.1
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• pp.137-143
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• 2014

Smart education in the information window, type talent in modern society is changing as talented smart shoes, smart automation creative talent through education, training can be called education revolution. In other words, the advent of smart devices, such as knowledge and information and to actively growing individual customized training paradigm change in the way education and training to reflect this approach. Therefore, in this paper, a smart learning environment based technologies for implementing the system was designed to be the next generation of cloud computing and N screen-based smart education system was studied. From this, educational functions and features in a smart media environment, based on the analysis of the utilization of a smart education system, which maximizes the system design were studied.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2009.01a
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• pp.311-315
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• 2009

The ubiquitous smart home is the home of future that takes advantage of context information from user and home environment and provides automatic home services for the user. User's location and motion are the most important contexts in the ubiquitous smart home. This paper presents a method positioning user's location using four cameras and some home context parameter together with user preferences provided. Some geometry math problems would be raised to figure out approximately which area is monitored by cameras. The moving object is detected within the image frames and then simulated in a 2D window to present visually where user is located and show his moving. The moving ways are statistically recorded and used for predicting user's future moving.

• International Journal of Internet, Broadcasting and Communication
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• v.12 no.4
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• pp.11-17
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• 2020

This paper proposed the design of a new window signage system architecture, which utilized a window of a building, with attached LED for visible light communication. In this paper, the proposed method using the LED strip to transmit light data and receive the data through a HMD with a smart device camera. The LED strip attached to the existing building window, as a part of semi-transparent signage. Semi-transparent signage based on a controllable LED strip-modules and attached to the window used to provide entertainment contents and the information service to people through optical camera communication (OCC) as well. Also, this work suggests using the camera supplied Head Mounted Device (HMD) as an OCC receiver. The LED attached window signage system structure described in this paper can be utilized in various buildings infrastructure like house, shopping areas, industrial building, etc.