• Korean Journal of Construction Engineering and Management
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• v.16 no.6
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• pp.31-40
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• 2015

The public housing needs maintenance administration for improvement and retainment of residential condition by means of tenants participation. However, most researchers have considered tenants as passive participants in this context. The previous studies did not comprehend perspective of tenants participation and just measured the management preference and the level of satisfaction on maintenance. This study investigates the attitudes and perceptions of tenants on participation in public housing maintenance by introduced Q method that provides a systematic and rigorous quantitative means for examining human subjectivity. The subjectivity is classified as types according to cost and benefit factors by principal components analysis and varimax rotation of the extracted factors. As a result, this study present 5 types of tenants participation and expect to discuss desirable roles of tenant and org anization in public housing maintenance.

• Korean Journal of Construction Engineering and Management
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• v.16 no.6
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• pp.136-143
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• 2015

Snow-melting system has been applied not only to roads for car traffic but also to pavement for the pedestrians safety reason in some of the developed countries such as USA and Canada based on countermeasures against Natural Disasters Act revised in 2000. Even though this system was introduced in korea in 2006 and has been partly applied to car traffic roads, there is few places that the system has been applied. Therefore, in this research a snow-melting system with a block-type to cover a pavement that efficiently transfers heat form heat rays to the top of a pavement and protects the heat rays. A quality check showed that compression and bending strength was improved approximately 5 times stronger and 7 to 10 times more absorption rate than the KS(Korea Industrial Standard) requirement. Moreover, only 10 minute was required to increase temperature above zero with a block-type snow-melting system whereas approximately 180 minute was spent with the existing system. This research is expected to contribute to environmental issues and reduce accidents on a slippery road.

• Korean Journal of Construction Engineering and Management
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• v.10 no.6
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• pp.135-145
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• 2009

The main goal of construction projects from the past has been enhancing efficiency by reducing cost and time. but, seeing the current condition of safety management of many construction companies nowadays, it is true that not much attention has been paid to safety management for a long time. However, there are paradigm shift from the cost and term of works to safety management in the construction industry, from this circumstance the safety management is evaluated more importantly. Though less accident happens compared to past, the accidents are getting greater because construction projects nowadays are bigger and more complex and monetary loss from the accidents are increasing. Also, the severity is getting greater and even fatal. For this reason, more improved safety management is very necessary. Therefore, we are to propose more efficient system for safety management in this thesis. Technical parts for developing system include many technique such as Real Time Locating system, and other techniques like Monitoring module based on BIM, Data Mart, Alarm are also applied together. Through this system, in the construction site, safety management is performed more effectively and widely because the system can manage the human resource and fluid situation. Also, safety manager can conduct more systematically and advanced safety management through human resource dominated safety management.

• Korean Journal of Construction Engineering and Management
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• v.9 no.4
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• pp.173-181
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• 2008

Last decade, Korea's export scale has resulted in remarkably increasing tendency, and the Korean construction firms(KCFs)' activities on the global markets also have been revitalized. Therefore, this paper analyze a correlation between changes in the oversee market conditions and firms' competitiveness focused on plant business. The aim of this paper is to analyze the internal competency change of the KCFs on the global markets in the past 5 years and to find gap of internal competencies between KCFs and outstanding foreign firms. From a survey analysis this paper found that the external impacts on the global markets(changes of exchange rates, raw materials prices, supply-demand conditions, etc.) have highly influenced the sales amount of the KCFs. But the impacts to change the operating profit have been analyzed as not important. So it is necessary to reinforce the KCF's internal competencies rater than expecting an improvement of the external conditions. Also, the KCFs should strengthen the design engineering as a core competency.

• Korean Journal of Construction Engineering and Management
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• v.14 no.3
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• pp.146-156
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• 2013

Recently, to reflect the various needs of customers in the apartment field, the customized apartment has emerged. From the point of the customer, customized apartments have the definite advantage of being able to guarantee more customer options. On the other hand, from the point of the project manager, there are significant risk factors, with increase of management factors, construction delays, etc. The reasons for this are, to date, the insufficient systematic analysis of the project, and the lack of experience of similar projects. This study provides the waste factors of each phase in a customized apartment project. A survey and interview are conducted to achieve the waste factors using MUDA methodology; a process of the project was analyzed; and a factor of each process was identified. Also, AHP(Analytic Hierarchy Process) are used, to evaluate the waste factors in project stages. The AHP results show that "Design change" and "Inappropriate intervention in construction process" ranked highly in the waste factors. The results of our research will provide a countermeasure that addresses waste factors in similar projects, and contributes to reducing the extra cost and time in new projects.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.2B
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• pp.117-128
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• 2006

For the legacy IEEE 802.15.3 WPAN protocol, an unpredictable piconet coordinator(PNC) leaving from a piconet without a proper handoff procedure causes an absence of PNC, and thus the piconet gets collapsed. In addition, several beacons from PNCs in adjacent piconets may be collided on a device(DEV) located between those piconets. This beacon collision eventually makes the DEV leave from the piconet. To remedy these two problems, we here propose an Active Seamless Coordinator Switching(ASCS) scheme and a PNC HB based Beacon Alignment(PHBA) one. In the ASCS scheme, a PNC assigns a number of DEVs as next possible PNCs in sequence for provisioning against the abrupt breakdown of the current active PNC. Each nominated DEV proactively sends a probe frame to confirm the operation status of the active PNC. For the case of no response from the PNC, the nominated DEV tries to become a new PNC immediately. In the second PHBA scheme, each PNC is allow to broadcast a special Heart Beat(HB) frame randomly during a superframe period. When a DEV receives a HB frame from other PNC, it promptly sends the related PNCs a special Hiccup Beat(HCB) frame with the superframe information of its associated PNC. As a result, the HCB frame makes both PNCs align their superframe beginning time in order to yield no more beacon collisions. For these two proposed schemes, we show the performance by simulations. We can confirm the enhancement of throughput for each superframe and average frame transfer delay, since each scheme can reduce the duration of piconet collapse. Finally, it is worth while to note that the proposed schemes can be operated with frames those are permitted in the legacy WPAN standard.

• Journal of the Economic Geographical Society of Korea
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• v.10 no.2
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• pp.223-238
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• 2007

Central government of Korea devised the balanced national development as one of important agenda of government administration, and set up special act for balanced national development. According to special act, a plan to transfer public institutions to local areas was publicized on June 24, 2005. Thus 175 public institutions located in the capital area will be transfered to 11 local governments, and innovative cities will be built in local areas until 2012. However, Gwangju and Jeonnam province adopted not two individual innovative cities but one common innovative city in cooperation with two local governments. This study focuses on the characteristics of location selection process of common innovative city in Gwangju and Jeonnam province. Discussion about construction of common innovative city was started in need of new model for common development of two provinces, and most of peoples agreed a plan to establish on common innovative city within Jeonnam area near Gwangju area. Gwangju Jeonnam Regional Innovation Council, in particular, played an important role in the process of location selection and initial discussion about common innovative city. In addition, Common innovative city to be built in Naju city will be provided positive regional development effects in several dimensions. In result, it has been evaluated as a successful model of innovative city to be constructed with transfer of public institutions to local areas.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.21 no.7
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• pp.761-768
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• 2010

This paper presents an effective method to achieve the wideband waveform for high resolution SAR(Synthetic Aperture Radar) using the frequency multiplication technique. And also this paper analyzes the root causes for the spectral regrowth due to 3rd-order intermodulation in chirp bandwidth expansion scheme using quadrature modulator and frequency multipliers. The amplitude and phase imbalance requirement are defined based on the simulation results in terms of quadrature channel imbalance. This minimizes the degradation of range resolution, peak sidelobe ratio and integrated sidelobe ratio. The wideband chirp generator using the frequency multiplier and memory map scheme was manufactured and the compensation technique was presented to reduce the spectral regrowth of SAR waveform by minimizing the amplitude and phase imbalance. After I and Q channel imbalance adjustment, the carrier level reduces －28.7 dBm to －53.4 dBm. Chirp signal with 150 MHz bandwidth at S-band expands to 600 MHz bandwidth at X-band. The sidelobe levels are reduced by about 8 to 9 dB by compensating the amplitude balance between I and Q channels.

• Journal of Environmental Policy
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• v.9 no.1
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• pp.57-81
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• 2010

Since the Republic of Korea is highly dependent on fossil fuels despite high oil prices, it urgently needs to renew its economic and social system to cut carbon emissions and achieve green growth. Therefore, reforming or eliminating subsidies related to the use of fossil fuels is a timely and oppropriate policy recommendation for Korea. It would be a win-win deal for Korean society as it would not only reduce the use of environmentally harmful fossil fuels but also enhance economic efficiency. In particular, cross-subsidies for industrial, agricultural and night thermal-storage power services make up more than 80 percent of all subsidies provided to the entire electric power industry sector of Korea. Of these cross-subsidies, this paper analyzes the electricity subsidy for industries, which takes up the largest share (about KRW 1.6583 trillion yearly), among the environmentally harmful subsidies in the electric power sector. Thus, the paper focuses on the analysis of ripple effect anticipated when this is reformed. To examine the effects of this subsidy reform, price elasticities were estimated using the ARDL (autoregressive distributed lag) model and quarterly data from 1990 to 2007. The main results of this study show that 1) annual energy demand for electric power in the industrial sector would drop by 12,475,930MWh and 2) $CO_2$ emissions would plummet by 2,644,897 tons per year if the subsidy were reformed. We can deduct from this that the abolition of environmentally harmful subsidies in the electric power sector in the Republic of Korea would considerably contribute to $CO_2$ emissions abatement in the country.

• The Journal of the Korea institute of electronic communication sciences
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• v.8 no.10
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• pp.1491-1497
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• 2013

Radio frequency identification (RFID) is an important and essential components of ubiquitous computing, with the development of wireless communication technologies and mobile computing environment. Recently, RFID becomes the mainstream application that helps fast handling and uniquely identifying the physical objects. It utilizes the electromagnetic energy for data transmission from a tag to a reader in the presence of arbitrary interference and noise. In order to employ the portable mobile RFID reader, a tag-collision problem between two or more adjacent tags should be considered. In this paper, we present the operation of RFID system in which numerous tags are present in the interrogation zone of a single reader at the same time. Since there may exist a number of tagged objects in the narrow area, multiple RFID tags may interfere each other, caused to degrade the data reliability and efficiency of the RFID system. In order to suppress interference signals from multiple neighboring tags, we present an application of Gold code for RFID communication system, which uses spread spectrum technique. In this RFID system, data bits are spreaded in each tags with the unique Gold code and the spreaded data bits are despreaded in the reader with the same Gold code. The performance analysis of the considered RFID anti-collision system is illustrated via computer simulation examples.