• International conference on construction engineering and project management
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• 2007.03a
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• pp.433-439
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• 2007

A ubiquitous environment in construction requires integrating hardware and software systems. Currently the Construction System Integration Lab (CSIL) at Pusan National University is currently studying the application of ubiquitous technology for better communication in the construction process. In this paper, a pilot of Ubiquitous Concrete Pour System (u-CPS) has been presented to demonstrate the effectiveness of data exchange in the concrete pour process. The u-CPS environment takes advantage of the RFID technology for collecting construction data. The pilot can automatically generate the data for concrete pour work such as departure time, arrival time, concrete pour time. Construction managers can keep track of the progress of concrete pour work using the information. A case study was done for a building construction using the pilot system, the result of which demonstrated that the RFID-base system can help improve the effectiveness of data communication during the concrete pour process.

• Proceedings of the Korea Information Processing Society Conference
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• 2021.11a
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• pp.118-121
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• 2021

슈퍼컴퓨터는 수백~수천 노드의 컴퓨팅 자원이 연결되어 복잡한 계산이나 대규모 데이터를 병렬 처리하며 일부 노드에서 발생하는 예상치 못한 문제는 전체적인 시스템 성능 저하로 이어질 수 있기 때문에 슈퍼컴퓨터 모니터링과 성능 분석은 슈퍼컴퓨터를 구축하고 운영하는데 필수적인 요소로 볼 수 있다. 본 논문에서는 오픈소스 소프트웨어인 Performance Co-Pilot, Bpftrace, Grafana를 활용한 슈퍼컴퓨터 모니터링 및 성능분석 시스템 구축 방안을 제안하였으며 이를 통해서 확장가능하면서도 유연한 구조의 슈퍼컴퓨터 모니터링 및 성능 분석이 가능함을 보였다.

• Journal of IKEEE
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• v.15 no.3
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• pp.235-240
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• 2011

The scattered pilots employed in DVB-T take advantage of the merits of both the block type and comb type pilot arrangement to increase the transmission efficiency. To estimate the channel transfer functions for data subcarriers, it is required to conduct time-frequency domain 2D estimation using the pilots. Though 2D Wiener estimator is optimal in sense of MSE (mean square error), it is too complex to implement in hardware. In this paper a new channel estimation method for the scattered pilot based OFDM system by measuring the power of AWGN and removing the noise in the LS (least square) estimate of the channel is proposed. And the simulation results reveal the proposed method outperforms the 2D linear interpolation in the fading channel.

• Korean Journal of Human Ecology
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• v.24 no.6
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• pp.887-901
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• 2015

This study aims to identify limitations and pending problems after reviewing the overall policies and status of rural Newtown projects, and to seek solutions to its problems. This study targeted the villages of 5 districts, which were developed as rural new-towns after 2009 and included the basic status and progress of the pilot districts. This study conducted a literature review to examine the basic status and progress of the pilot districts, and based on this, analyzed the demand prediction, site selection, project implementation, and housing and amenity facilities of the pilot districts. The study methods included literature reviews, on-site surveys, interviews with village representatives, and consultations with experts. According to the analysis results, a low occupancy rate of the Newtown project districts is because the prediction of occupancy demand was incorrectly completed before implementing the projects. Also, the eligibility for occupancy, such as age restriction and mandatory farming was too strict. Other problems included an absence of income generation support policies for rural returnees, a housing supply policy in disregard of agricultural characteristics, and a lack of understanding of maintenance of communal space, etc.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.7C
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• pp.481-487
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• 2011

Cyclic delay diversity (CDD) is a simple transmit diversity technique for an OFDM system using multiple transmit antennas. However, the performance of post-FFT estimation, i.e., integer frequency offset (lFO) is deteriorated by high frequency selectivity introduced by CDD. In this paper, the IFO estimation scheme is proposed for OFDM-based DRM+ system with CDD. Based on the pilot subset partitioning, the proposed IFO estimation scheme reduces the effect of performance degradation caused by frequency selectivity in OFDM systems with CDD . The simulation results show that the performance of the proposed IFO estimator is significantly improved when compared to that of the conventional IFO estimator.

• Korean Journal of Child Studies
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• v.15 no.1
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• pp.5-21
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• 1994

The purpose of this study was to develop a scale for evaluation of early childhood programs in Korea. The procedures included content validation and a pilot test. A total of 192 items in 10 major areas was developed based on the review of literature and discussions with professionals in early childhood education. The 10 areas include: scheduling, curriculum, interation, physical environment, materials, nutrition, health and safety, administration, staff qualifications, relationships with parents, and evaluation. The pilot scale was administered to 428 classroom teachers and directors, and 47 college professors in early childhood education. The items were rated on a 3-point scale in terms of importance as evaluation criteria. The methods for data analysis included item means and standard deviations for content validation, Cronbach ${\alpha}$ for reliability, and factor analysis for construct validity. Most items in 10 areas were rated as moderate to highly important (average 2.3), especially items in curriculum and staff qualifications. Two factors emerged from the data: institutional management, and curricular planning and implementation. The Cronbach ${\alpha}$ levels were .70 or higher in most areas, but the range covers from .48 to .91. Based on the pilot data, 143 items were selected for the second year study.

• Healthcare Informatics Research
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• v.24 no.4
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• pp.387-393
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• 2018

Objectives: This paper describes an experience of implementing seamless service trials online and offline by adopting Internet of Things (IoT) technology based on near-field communication (NFC) tags and Bluetooth low-energy (BLE) beacons. The services were provided for both patients and health professionals. Methods: The pilot services were implemented to enhance healthcare service quality, improve patient safety, and provide an effective business process to health professionals in a tertiary hospital in Seoul, Korea. The services to enhance healthcare service quality include healing tours, cancer information/education, psychological assessments, indoor navigation, and exercise volume checking. The services to improve patient safety are monitoring of high-risk inpatients and delivery of real-time health information in emergency situations. In addition, the services to provide an effective business process to health professionals include surveys and web services for patient management. Results: Considering the sustainability of the pilot services, we decided to pause navigation and patient monitoring services until the interference problem could be completely resolved because beacon signal interference significantly influences the quality of services. On the other hand, we had to continue to provide new wearable beacons to high-risk patients because of hygiene issues, so the cost increased over time and was much higher than expected. Conclusions: To make the smart connected hospital services sustainable, technical feasibility (e.g., beacon signal interference), economic feasibility (e.g., continuous provision of new necklace beacons), and organizational commitment and support (e.g., renewal of new alternative medical devices and infrastructure) are required.

• ETRI Journal
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• v.43 no.5
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• pp.941-949
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• 2021

In this study, a spatial spectrum method is proposed to cope with the pilot spoofing attack (PSA) problem by exploiting the of uplink-downlink channel reciprocity in time-division-duplex multiple-input multiple-output systems. First, the spoofing attack in the uplink stage is detected by a threshold derived from the predefined false alarm based on the estimated spatial spectrum. When the PSA occurs, the transmitter (That is Alice) can detect either one or two spatial spectrum peaks. Then, the legitimate user (That is Bob) and Eve are recognized in the downlink stage via the channel reciprocity property based on the difference between the spatial spectra if PSA occurs. This way, the presence of Eve and the direction of arrival of Eve and Bob can be identified at the transmitter end. Because noise is suppressed by a spatial spectrum, the detection performance is reliable even for low signal-noise ratios and a short training length. Consequently, Bob can use beamforming to transmit secure information during the data transmission stage. Theoretical analysis and numerical simulations are performed to evaluate the performance of the proposed scheme compared with conventional methods.

• Current Optics and Photonics
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• v.8 no.4
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• pp.345-354
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• 2024

The bit walk-off effect caused by fiber dispersion and carrier reuse in the base station (BS) are two key problems in radio-over-fiber (ROF) systems. In this paper, a novel frequency-octupling ROF system based on the Mach-Zehnder modulator (MZM) is proposed, which can overcome the bit walk-off effect and realize carrier reuse by inserting pilot signals. Theoretical analysis and simulation verification of the system are carried out. Under the condition of a Q factor greater than 6, the optical fiber transmission distance of the upper and lower links is more than 290 km and 80 km, respectively. The influence of the main device parameters of the system on the Q factor is analyzed when they deviate from their designed values. The system designed in this paper can not only effectively overcome the bit walk-off effect, but also solve the problem of downlink performance degradation and the limitation of tunability caused by conventional carrier reuse in ROF. The system can greatly increase the transmission distance and improve the performance of the system and has an important application prospect in ROF.

• 한국항공운항학회:학술대회논문집
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• 2006.05a
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• pp.61-66
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• 2006