• ETRI Journal
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• v.30 no.2
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• pp.249-254
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• 2008

In this paper, we demonstrate an electrically band-limited carrier-suppressed return-to-zero (EB-CSRZ) signal generator operating up to a 10 Gbps data rate comprising a single-stage Mach-Zehnder modulator and a wideband signal mixer. The wideband signal mixer comprises inverter stages, a mixing stage, and a gain amplifier. It is implemented by using a 0.13 ${\mu}m$ CMOS technology. Its transmission response shows a frequency range from DC to 6.4 GHz, and the isolation response between data and clock signals is about 21 dB at 6.4 GHz. Experimental results show optical spectral narrowing due to incorporating an electrical band-limiting filter and some waveform distortion due to bandwidth limitation by the filter. At 10 Gbps transmission, the chromatic dispersion tolerance of the EB-CSRZ signal is better than that of NRZ-modulated signal in single-mode fiber.

• International Journal of Aeronautical and Space Sciences
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• v.12 no.2
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• pp.163-174
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• 2011

Task assignments of multiple unmanned aerial vehicles (UAVs) are examined. The phrase "task assignment" comprises the decision making procedures of a UAV group. In this study, an on-line decentralized task assignment algorithm is proposed for an autonomous UAV group. The proposed method is divided into two stages: an order optimization stage and a communications and negotiation stage. A genetic algorithm and negotiation strategy based on one-to-one communication is adopted for each stage. Through the proposed algorithm, decentralized task assignments can be applied to dynamic environments in which sensing range and communication are limited. The performance of the proposed algorithm is verified by performing numerical simulations.

• Radiation Oncology Journal
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• v.33 no.2
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• pp.57-65
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• 2015

Stereotactic body radiotherapy (SBRT) represents a consolidated treatment option for patients with medically inoperable early stage non-small cell lung cancer (NSCLC). The clinical evidence accumulated in the past decade supports its use as an alternative to surgery with comparable survival outcomes. Due to its limited toxicity, SBRT is also applicable to elderly patients with very poor baseline pulmonary function or other severe comorbidities. Recent comparative studies in operable patients raised the issue of the possible use of SBRT also for this subgroup, with quite promising results that still should be fully confirmed by prospective trials with long-term follow-up. Aim of this review is to summarize and discuss the major studies conducted over the years on SBRT and to provide data on the efficacy and toxicity of this radiotherapy technique for stage I NSCLC. Technical aspects and quality of life related issues are also discussed, with the goal to provide information on the current role and limitations of SBRT in clinical practice.

• Radiation Oncology Journal
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• v.35 no.2
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• pp.185-188
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• 2017

Primary liver tumor, especially hepatocellular carcinoma (HCC), is a common cause of cancer death worldwide. The incidence is generally higher in Asian countries than in western countries. Carcinogenesis of HCC is often associated with hepatitis viral infections. Current standard treatment of HCC is surgical resection or transplantation in patients with early stage disease. However, the patient with advanced stage disease, surgical resection is often limited. Sorafenib or other treatment modalities are not so effective as well. We report a case of unusual radiation super-sensitivity in advanced stage HCC, and review the literature.

• Proceedings of the KSME Conference
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• 2002.08a
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• pp.577-580
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• 2002

In this paper, the pumping performance of the disk-type drag pump which works in the outlet pressure range from 4 to 0.001 Torr is studied experimentally. The pumping characteristics of various drag pumps are performed. The inlet pressures are measured for various outlet pressures of the test pump. The flow-meter method is adopted to calculate the pumping speed. Compression ratios and pumping speeds for the nitrogen gas are measured. The present experimental data show the leak-limited value of the compression ratio in the molecular transition region. The rotational speed of the pump is 24,000rpm. The inlet pressures are measured for various outlet pressures of the test pump. The ultimate Pressures for zero throughput are measured for three-stage, two-stage and single-stage disk-type, respectively.

• Journal of Korean Port Research
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• v.12 no.1
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• pp.131-143
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• 1998

This paper presents derivation of stage-discharge curve for Yangsan river. To derivate of stage-discharge lationship is one of the essential research areas in the water resource field. It provides reliable data a long term planning and hydrologic quantity on water resource development by quantitative analysis. The rating curve derivated through 15 discharge-observation on Yangsan river basin in 1997 has been estimated Q=1283.0262-1553.3158H+477.2702H2. According to the rating curve, the highest water level 2.6m, the limited water-level should be bound to the maximum of 2.6m. Before this research, stage-discharge curve of Yangsan river has not been developed, and only 15 discharge observation(hydrometry) has been carried out though this research. Therefore it seems necessary to collect observation data through a long term process to obtain a reliable rating curve equation.

• Journal of Bio-Environment Control
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• v.6 no.1
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• pp.27-33
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• 1997

This experiment was carried out to investigate the effects of limited nutrient supply during 21 days before and after pollination stage on the growth, fruit quality and nutrient uptake of muskmelon in rockwool culture. Muskmelon, cv. Earl's Favorite seeds sowed on rockwool cube and transplanted on rockwool slab($90\times15\times7.5cm$) when 2 to 3 true leaf appeared on Sep. 6, 1991. Three kinds of nutrient composition recommended by Shizuoka university, combinated with the composition of Otsuka house A and composition Shizuoka III. One half of calcium nitrate(Ca(NO$_3$)$_2$.4$H_2O$) for limiting nitrogen supply during 21 days was treated and then fertigated the nutrient composition recommended by Shizuoka university up to harvest time. Trickling nozzles(Netafim Co. Israel) were used for fertigation of nutrient solution and noncirculating system was employed. Temperature was maintained $18^{\circ}C$ in night but 23 to $25^{\circ}C$ for 10 days after pollination for softening the fruit. The drainage ratio of nutrient solution was adjusted 20 to 30 percent. Fertigated and drained amount, and the pH and EC of nutrient solution were recorded. The concentrations of mineral elements including N, P, K, Ca, and Mg were analyzed and compared among treatments. In both autumn and winter cultivation, the limitation of nutrient supply by adjustment of nutrient composition(NO$_3$-N : 8meㆍ$\ell^{-1}$) caused the nutrient deficiency in muskmelon plant due to the limited nutrient supply. After pollination nutrient limitation by the lowering the nitrate retarded the over thickening of upper leaves of muskmelon but plant height and fresh weight of fruit were higher in the plot of nonlimited nutrient supply. The phenomena were attributed to the differences of the amount of nutrient uptake due to the limited time of nutrient solution, duration of nutrient supply and concentration of nutrient solution. These results suggested that increasing nutrient supply in the pollination stage was favorable for better appearance of fruit and improving fruit quality. Further trials would be required for the incre-ment of sugar degree of muskmelon grown in rockwool.

• The Journal of the Acoustical Society of Korea
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• v.37 no.5
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• pp.356-362
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• 2018

Stage in classical shoebox type concert hall is placed and occupy one side of the hall and have much early reflections from surrounded walls and ceiling nearby. On the other hand stage in vinyard terrace concert hall, which is surrounded by terrace seats instead of walls and ceiling, has lack of early reflections which may cause lack of communications among the players. Vinyard hall stage is enclosed with terrace seats front walls, while the players located on the stage riser keep the walls off as the walls have limited heights. Ensemble reflector installed above the stage is an effective way for the players to monitor the sound produced on the stage. That may help achieving a good ensemble of the performance. Ensemble reflector over the stage of a large vinyard terrace hall of 2,000 seats was designed with the variables of the location, the shape and the area. The effectiveness of the ensemble reflector is verified with the parameter of stage support.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.35S no.6
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• pp.1-8
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• 1998

This paper presents an asynchronous DS/CDMA multiuser detector, which is a two stage, symbol-by-symbol scheme consisting of conventional detectors followed by linear decorrelating detectors. The conventional detector first makes temporal decisions and the detected symbols are delayed by one symbol period to be used for the selection of decorrelating bases in the subsequent decorrelaing detection stage. It also employs a bank of early-late correlators in place of a bank of single correlators taking the small offset of chip timing asynchronism into account. The proposed detector requires only the coarse knowledge of relative time delays of interfering users and is suitable for digital implementation. To verify the detector performance, the analytical BER performance will be given and compared with the simulation results for BPSK DS/CDMA signals in AWGN channel. While the performance of the proposed detector will be analyzed for time-limited signal, the simulation is carried out for both the time-limited and band-limited signals. As can be seen in the simulation results, the proposed scheme shows good results.

• Journal of the Korean Institute of Educational Facilities
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• v.25 no.6
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• pp.35-44
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• 2018

The purpose of this study is to predict more accurate construction costs and to support efficient decision making in the planning and design stages of smart education facilities. The higher the error in the projected cost, the more risk a project manager takes. If the manager can predict a more accurate construction cost in the early stages of a project, he/she can secure a decision period and support a more rational decision. During the planning and design stages, there is a limited amount of variables that can be selected for the estimating model. Moreover, since the number of completed smart schools is limited, there is little data. In this study, various artificial intelligence models were used to accurately predict the construction cost in the planning and design phase with limited variables and lack of performance data. A theoretical study on an artificial neural network and deep learning was carried out. As the artificial neural network has frequent problems of overfitting, it is found that there is a problem in practical application. In order to overcome the problem, this study suggests that the improved models of Deep Neural Network and Deep Belief Network are more effective in making accurate predictions. Deep Neural Network (DNN) and Deep Belief Network (DBN) models were constructed for the prediction of construction cost. Average Error Rate and Root Mean Square Error (RMSE) were calculated to compare the error and accuracy of those models. This study proposes a cost prediction model that can be used practically in the planning and design stages.