• 한국도로학회논문집
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• 제20권2호
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• pp.9-17
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• 2018

PURPOSES : The frequency and severity of natural disasters such as torrential rain or typhoons have become increasingly significant worldwide. Events such as summer typhoons and localized torrential downpour can cause severe damages to a residential area and road networks, resulting in serious harm to the daily lives of people, especially in rural areas by isolating residents from road networks. An immediate and emergency repair technology for the collapsed road networks is urgently needed. This study introduces a new technology to repair road bases or slopes. METHODS : The development of new technology for emergency and permanent repair consists of first, packing of cement paste-coated gravel, second, combining appropriate equipment, and third, conducting a field applicability test. In this research, the compressive strength of cement pastecoated gravel, gravel-netting concrete properties, and packing efficiency were determined, and a full scale field mock-up test was carried out. RESULTS : The compressive strength of the cement paste-coated gravel concrete satisfied the required limit for road base of 5 MPa after 7 days. With appropriate netting materials and packing size, gravel-netting concrete was successful up to a slope of 1:1.5. The full scale field mock-up test showed efficiency in the field and penetration resistance performance. CONCLUSIONS : The new technology of emergency and permanent repair for damaged road bases and slopes, introduced in this study, showed satisfactory performance. The technology is expected to be applied in the field when construction procedures and quality specifications are made.

• 한국항행학회논문지
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• 제26권6호
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• pp.481-486
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• 2022

최근 IoT(Internet of Things)의 급속한 성장은 저 전력 무선 기술의 확산으로 이어지고 있다. IoT 무선 네트워크 설계의 주요 과제는 2.4 [GHz] ISM(Industrial Scientific Medical) 주파수 대역을 공유하는 서로 다른 무선 기술 간의 공존을 달성하는 것이다. 따라서 무선 네트워크의 신뢰성 향상과 무선 네트워크 사이의 공존 운용을 위한 연구가 필요하다. 특히, 다양한 산업 분야에서 장치 간의 연결 매체로 많은 활용이 예상되는 BLE(Bluetooth Low Energy) 무선 네트워크 환경에서 상호 서비스 공존을 위한 간섭 모델 및 성능에 대한 연구가 필요하다. 본 논문에서는 주거 및 산업용 무선 응용 분야에서 널리 사용되는 BLE 시스템의 물리적 계층을 중심으로 IEEE 802.15.4 시스템과의 동일채널간섭 모델을 설정하고 동일채널간섭 환경에서 BLE 무선 통신 시스템의 성능을 분석한다. 분석 결과, 잡음과 동일채널간섭이 존재하는 환경에서 간섭원과 BLE 시스템 사이의 거리가 증가함에 따라서 동일채널간섭의 양이 감소하여 BLE 시스템의 오율 성능은 개선됨을 알 수 있었다.

• Journal of Communications and Networks
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• 제5권4호
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• pp.303-308
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• 2003

We present a statistical model for the path loss of ultrawideband (UWB) channels in indoor environments. In contrast to our previously reported measurements, the data reported here are for a bandwidth of 6GHz rather than 1.25GHz; they encompass commercial buildings in addition to single-family homes (20 of each); and local spatial averaging is included. As before, the center frequency is 5.0GHz. Separate models are given for commercial and residential environments and, within each category, for lineof sight (LOS) and non-line-of-sight (NLS) paths. All four models have the same mathematical structure, differing only in their numerical parameters. The two new models (LOS and NLS) for residences closely match those derived from the previous measurements, thus affirming the stability of our path loss modeling. We find, also, that the path loss statistics for the two categories of buildings are quite similar.

• 한국환경과학회지
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• 제13권2호
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• pp.109-116
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• 2004

Nagan walled town is located on an axis connecting symbolic places, which is a lucky place from the Fengshui point of view because a mountain sits to the rear and a body of water sits to the front. It represents the environmental development of cultural space by blending folk belief, religion, social systems, adminstration facilities and living culture buildings. Therefore, it has a sustainable cultural view connected with a formed or formless religious view and an artificial view (walls, government buildings, living houses, cultivated lands, etc.) in a natural landscape. Environmental design techniques, enlarging the meaning and value of living on a mental level, can be found in the arrangement of space composition and settlement of Nagan walled town. The organised spaces of government and residential areas were constructed within the wall with the view of searching for lucky places (from best, better and good places) in order to construct ecological networks according to the outlooks of space and settlement.

• Architectural research
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• 제15권1호
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• pp.1-8
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• 2013

Over the past two decades following the 1990s, South Korea's IT industry has developed rapidly. In keeping with this trend, the architectural and urban planning sectors have also converged with IT and achieved advancement in new directions. This evolution includes a variety of conceptual terminologies such as 'home automation', ''home network', 'smart home, and 'ubiquitous-city'. However, smart homes and U-cities simply represent a conceptual extension of home networks, and there is little real difference in the technologies involved. In particular, U-cities remain focused on infrastructure rather than on the development of specific content; consequently, they have failed to demonstrate distinctive features to clearly differentiate themselves from conventional cities. In such a context, this research aims at the proposal of a 'ubiquitous pavilion' as a component of the efforts to develop a range of architectural contents that utilize ubiquitous technologies. By grafting the pavilion, one of the most basic forms in architecture, with cutting-edge ubiquitous technologies, this paper intends to suggest a multi-purpose architectural space readily and simply available not only in newly emerging U-cities, but to conventional cities as well.

• Journal of Communications and Networks
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• 제14권6호
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• pp.672-681
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• 2012

A potential breakthrough of the electrification of the vehicle fleet will incur a steep rise in the load on the electrical power grid. To avoid huge grid investments, coordinated charging of those vehicles is a must. In this paper, we assess algorithms to schedule charging of plug-in (hybrid) electric vehicles as to minimize the additional peak load they might cause. We first introduce two approaches, one based on a classical optimization approach using quadratic programming, and a second one, market based coordination, which is a multi-agent system that uses bidding on a virtual market to reach an equilibrium price that matches demand and supply. We benchmark these two methods against each other, as well as to a baseline scenario of uncontrolled charging. Our simulation results covering a residential area with 63 households show that controlled charging reduces peak load, load variability, and deviations from the nominal grid voltage.

• KIEE International Transactions on Power Engineering
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• 제2A권4호
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• pp.136-144
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• 2002

Load models are very important for improving the accuracy of stability analysis and load flow studies. Various loads are connected to a power bus and their characteristics of power consumption change with voltage and frequency. Thus, the effect of voltage/frequency changes must be considered in load modeling. In this work, artificial neural networks-ANNs- were used to construct the component load models for more accurate modeling. A typical residential load was selected and subjected to a test under variable voltage/frequency conditions. Acquired data were used to construct component models by ANNs. The aggregation process of separately determined load models is also presented in the paper. Furthermore, this paper proposes a method to transform a single load model constructed by the aggregation method into a mathematical load model that can be used in traditional power system analysis software.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 하계학술대회 논문집 G
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• pp.2495-2497
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• 1998

Fiber optic facilities are increasingly being deployed in loop applications for both busines and residential areas. These facilities support a variety of communications services that include high speed data and video using leading technologies such as Synchronous Optical Network (SONET), Wavelength Division Multiplexing(WDM). This proliferation of fiber optic facilities combined with the increasing pressure on network operators to reduce costs are fostering increased automation to reduce labor costs associated with providing and maintaining communications services. Effective fiber management and accurate records can improve the reliability and integrity of the future telecommunications networks and the quality of customer services. This paper describes the trend forward and the need for the deployment of Fiber Administration System (FAS) into the operations enviroment of a typical network provider.

• 국제학술발표논문집
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• The 6th International Conference on Construction Engineering and Project Management
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• pp.723-727
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• 2015

Building energy use estimation relies on building characteristics, its energy systems, occupants, and weather. Energy estimation of new buildings is considerably an easy task when compared to modeling existing buildings as they require calibration with actual data. Particularly, when energy estimation of existing building stock is warranted at a city-scale, the problem is exacerbated owing to lack of construction drawings and other engineering specifications. However, as collection of buildings and other infrastructure constitute cities, such predictions are a necessary component of developing and maintaining sustainable cities. This paper uses Artificial Neural Network techniques to predict electricity consumption for residential buildings situated in the City of Gainesville, Florida. With the use of 32,813 samples of data vectors that comprise of building floor area, built year, number of stories, and range of monthly energy consumption, this paper extends the prediction to environmental impact assessment of electricity usage at the urban-scale. Among others, one of the applications of the proposed model discussed in this paper is the study of urban scale Life Cycle Assessment, and other decisions related to creating sustainable cities.

• 한국정보통신학회논문지
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• 제5권7호
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• pp.1238-1244
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• 2001

광대역 액세스 망에서 합류, 분배 지점에서의 효율을 고려한 광 수동망 설계는 중요하다. 광수동망 구조는 매우 간단하지만, 가입자들에서 발생되는 상향 트래픽 제어를 위해서는 매체 접근 제어 프로토콜이 필요하다. 한편, 사무실 환경을 위한 통신규약은 이미 표준화되어 있다. 광대역 통신망과 다양한 가전 제품의 증가에 의해 홈 네트워크 구성은 자연스러운 일이 되었다. 가정에서 사용하는 네트워크 응용 범위가 넓어짐에 따라 액세스 망과 여러 형태의 트래픽을 발생시키는 홈 네트워크 환경을 고려하였다. Global-FIFO 는 매우 간단하고, 기본적으로 요추-허용 메카니즘의 동적인 상향 대역 할당방식을 사용한다. 이것은 셀을 기본 단위로 한 효율적인 대역을 사용할 수는 있지만, 다양한 형태의 트래픽을 취급하는 홈 네트워크에는 적합하지 않다. 본 논문에서, 우리는 ATM-PON과 홈 네트워크 환경에 적합한 성능을 제어하는 MQ-FIFO라는 새로운 자원할당 MAC 알고리즘을 설계하고 분석한다.