• KSII Transactions on Internet and Information Systems (TIIS)
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• 제10권4호
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• pp.1611-1629
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• 2016

Recently, deploying WiFi access points (APs) for facilitating indoor localization has attracted increasing attention. However, most existing mechanisms in this aspect are typically simulation based and further they did not consider how to jointly utilize pre-existing APs in target environment and newly deployed APs for achieving high localization performance. In this paper, we propose a measurement-based AP deployment mechanism (MAPD) for placing APs in target indoor environment for assisting fingerprint based indoor localization. In the mechanism design, MAPD takes full consideration of pre-existing APs to assist the selection of good candidate positions for deploying new APs. For this purpose, we first choose a number of candidate positions with low location accuracy on a radio map calibrated using the pre-existing APs and then use over-deployment and on-site measurement to determine the actual positions for AP deployment. MAPD uses minimal mean location error and progressive greedy search for actual AP position selection. Experimental results demonstrate that MAPD can largely reduce the localization error as compared with existing work.

• 전기학회논문지
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• 제68권3호
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• pp.471-479
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• 2019

This research proposes a indoor magnetic map matching algorithm that improves the position accuracy by employing multiple magnetic sensors and probabilistic candidate weighting function. Since the magnetic field is easily distorted by the surrounding environment, the distorted magnetic field can be used for position mapping, and multiple sensor configuration is useful to improve mapping accuracy. Nevertheless, the position error is likely to increase because the external magnetic disturbances have repeated pattern in indoor environment and several points have similar magnetic field distortion characteristics. Those errors cause large position error, which reduces the accuracy of the position detection. In order to solve this problem, we propose a method to reduce the error using multiple sensors and likelihood boundaries that uses human walking characteristics. Also, to reduce the maximum position error, we propose an algorithm that weights according to their importance. We performed indoor walking tests to evaluate the performance of the algorithm and analyzed the position detection error rate and maximum distance error. From the results we can confirm that the accuracy of position detection is greatly improved.

• Spatial Information Research
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• 제21권2호
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• pp.1-9
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• 2013

최근 이동통신 기술의 발전으로 실내에서의 위치 획득 기술이 용이해지면서 실내 내비게이션 시스템에 대한 연구가 각광을 받고 있다. 최적화된 실내 내비게이션은 크고 복잡한 실내에서의 활동을 위해 빠른 경로를 제공한다. 그러나 기존의 실내 내비게이션 알고리즘 연구들에서는 공간 토폴로지 또는 실내 네트워크에 기반하여 대략적인 경로를 도출한다. 본 논문에서는 공간 토폴로지 분석과 실내 내트워크를 통합 분석하여 실내 경로를 계산하는 알고리즘을 제안한다. 제안 알고리즘은 전문적인 실내지도가 아닌 간소화된 실내 지도 데이터를 활용하여 실내 네트워크와 공간 토폴로지의 혼합 분석을 통해 실내 경로의 길이를 줄일 수 있다. 성능평가를 통해 FT-Indoornavi 알고리즘이 기존의 엘라스틱 알고리즘과 iNav 알고리즘보다 더 빨리 실내 경로를 계산할 수 있음을 보여준다.

• KIEAE Journal
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• 제13권4호
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• pp.27-32
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• 2013

This study focus on shaft box facade, special form of box window construction. It consists of a system of box window with continuous vertical shafts that extend over a number of stories to create a stack effect. The subject building was decided by analyzing various types of exiting apartments. Shaft box type balcony was devised by setting up shaft space at a part of balcony. Air flow and indoor air temperature were simulated, performance of shaft box type balcony was compared with existing types using VE computer simulation program. Research consequence can be summarized as follow: 1) In the case of existing types, the change of window opening rate has only a little effect on the improvement of indoor temperature. But, air flow rate increased two times in the case that changed opening rate 20% to 40% 2) In the case of existing types, the growth of air flow rate has little effect on the improvement of indoor temperature. But, shaft box type represented the remarkable effect on the improvement of indoor temperature as well as the growth of air flow rate.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2003년도 The Fifth Asian Computational Fluid Dynamics Conference
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• pp.207-208
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• 2003

Increasing interest in indoor air quality (IAQ) control has been found because of its serious effect on human health. To evaluate IAQ, thermal comfort in terms of temperature and velocity distributions of indoor air has to be analyzed in detail. Choice of location for installation of air-conditioner in a building will affect the performance of cooling effect and thermal comfort on the occupants, which in turn will affect the indoor air quality (IAQ) of the building. In this paper, we present a discussion on the proper location of the air-conditioner in order to obtain good thermal comfort for occupant of a typical bedroom in Macao. A set of carefully designed numerical experiments is run with the Computational Fluid Dynamics (CFD) software FLOVENT 3.2 [1]. Reynolds averaged Navier-Stokes equations are solved with finite volume technique and turbulence effects upon the mean flow characteristics is modeled with the k - & model. Assumption of steady state environment is made and only convective and conductive heat transfer from the occupant and air-conditioner are being concerned.

• KIEAE Journal
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• 제16권2호
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• pp.5-10
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• 2016

Purpose: Recently, many public office buildings which were built by curtain wall increased rapidly, but the results of the investigation of the government, these buildings have been found that the heating and cooling thermal load is high, and showed low energy efficiency. Method: To evaluate the effects by applying outdoor louver and indoor blind, which can control solar radiation in order to reduce the heating and cooling load of public office building which was built by glass curtain wall. The heating and cooling load was calculated via Energyplus, building and outdoor louver, indoor blind were modeled by Google sketchup connected to Energyplus. Result: The results of this study were as follows; the case of applying various outdoor louver, the heating and cooling load all decreased as compared to the case without applying outdoor louver, the case of applying indoor blind, the heating and cooling load decreased as compared to the case without applying indoor blind, but indoor blind showed low energy performance comparing outdoor louver.

• 한국가시화정보학회지
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• 제14권1호
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• pp.19-26
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• 2016

Modern people spend much time at indoor space. So, People want to make better indoor air condition. But the facade of building is made of glass to be seen urbanely, the effect of solar radiation makes indoor environment worse. This study designs an open space affected by solar radiation with 4-way cassette air-conditioner. Using numerical simulation, this paper investigates thermal comfort and ventilation performance with discharge angles $30^{\circ}$ and $45^{\circ}$. To study thermal comfort, this paper studies distribution of velocity, temperature and effective draft temperature. Also, this paper introduces concept of air age to study ventilation performance. The flow influenced by solar radiation determines thermal comfort and ventilation performance in room space. This study shows that discharge angle of 45 degree has better thermal comfort and ventilation performance than that of 30 degree.

• 공학교육연구
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• 제13권5호
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• pp.76-80
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• 2010

In this paper, the Location Compensation Mechanism using equivalent distance rate ($LCM_{edr}$) for localization system based on SDS-TWR (Symmetric Double-Sided Two-Way Ranging) in wireless sensor network is proposed. The performance of the mechanism is experimented in terms of two types of the localization tracking scenarios of indoor and outdoor environments in university campus. From the experimentations, the compensation ratio in the $LCM_{edr}$ is better than that in SDS-TWR about 90% in indoor/outdoor environments in scenario 1 but also is better than that of SDS-TWR about 91.7% in indoor environment and about 100% in outdoor environment in scenario 2 respectively.

• 로봇학회논문지
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• 제4권4호
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• pp.312-319
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• 2009

This paper proposes a low-complexity indoor localization method of mobile robot under the dynamic environment by fusing the landmark image information from an ordinary camera and the distance information from sensor nodes in an indoor environment, which is based on sensor network. Basically, the sensor network provides an effective method for the mobile robot to adapt to environmental changes and guides it across a geographical network area. To enhance the performance of localization, we used an ordinary CCD camera and the artificial landmarks, which are devised for self-localization. Experimental results show that the real-time localization of mobile robot can be achieved with robustness and accurateness using the proposed localization method.

• 한국대기환경학회지
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• 제6권1호
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• pp.97-102
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• 1990

A pilot field study was conducted to measure indoor and personal exposure to carbon monoxide (CO) levels using personal monitors from January to February in 1989. The principal objectives of the study was to design and evaluate the research protocol and the instrumentation performance for application to the conduct of a large-scale personal monitoring program. The mean CO concentrations in kitchen and in bedroom were 23.4 and 11.9 ppm, respectively, while mean concentration of personal CO exposure was 18.9 ppm. It was found that the mean CO concentrations in kitchen exceeded 20 ppm of the Korea ambient CO standard(8-hr average) not to be exceeded more than three times per year. The results suggest that indoor CO levels in Korean houses appear to be affected by use of coal briquette for heating any cooking.