• Journal of Construction Engineering and Project Management
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• v.5 no.2
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• pp.16-23
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• 2015

In this paper, a survey related to excavation construction activities among national and international construction companies was conducted to evaluate site productivity in construction industry. To analyze the respective productivity levels of each construction company, a benchmarking measures analysis that featured calculations of the performance ratio (PR) and performance management index (PMI) was performed. As a result of these analyses, it has been found that the work performed by local companies was marked by lower productivity and that of international companies was characterized by good productivity. Further analysis of construction workforce resources P% revealed that a construction company's productivity is largely dependent on production capacity and consumption resources, which means that the retention of skilled workers and utilization of high-quality resources yields the highest level of productivity. These results suggest that for a local construction company to be competitive in the construction work market, it must retrain skilled craftspeople, foremen, engineers, and project managers, and strengthen its building capability by leveraging new equipment and technologies.

• Journal of the Korean Solar Energy Society
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• v.38 no.1
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• pp.37-44
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• 2018

Solar panels are modules made up of many cells, like the N-type monosilicon, P-type monosilicon, P-type multisilicon, amorphous thin-film silicon, and CIGS solar cells. An efficient photovoltaic (PV) power is important to use to determine what kind of cell types are used because residential solar systems receive attention. In this study, we used 3-type solar panels - such as N-type monosilicon, P-type monosilicon, and CIGS solar cells - to investigate what kind of solar panel on a house or building performs the best. PV systems were composed of 3-type solar panels on the roof with each ~1.8 kW nominal power. N-type monosilicon solar panel resulted in the best power generation when monitored. Capacity Utilization Factor (CUF) and Performance Ratio (PR) of the N-type Si solar panel were 14.6% and 75% respectively. In comparison, N-type monosilicon and CIGS solar panels showed higher performance in power generation than P-type monosilicon solar power with increasing solar irradiance.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.30 no.5
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• pp.397-404
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• 2017

The purpose of this study is to evaluate the seismic performance of Staggered Truss Frame(STF) system while changing a shape of truss. The model of this project is a office building of ten floors with Pratt, Howe, Warren, K and Vierendeel truss system applied on each model. Next step is to select the section of elements which satisfy the highest demand capacity ratio by structure design considering gravity load, earthquake load and wind load and then calculate natural period, base shear and story drifts. On the basis of these values, Capacity Spectrum Method(CSM) shows the plastic behavior of STF system such as performance point of Design Earthquake(DE) and Maximum Considered Earthquake(MCE), yield state, plastic hinge etc. to be compared with other truss systems. As a result, Vierendeel STF system especially was found to have the highest strength and stiffness to the corresponding earthquake and all the models for each truss shape fulfilled the target performance level.

• KIEAE Journal
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• v.15 no.4
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• pp.85-90
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• 2015

Purpose: In design and planning Building Integrated Photovoltaic(BIPV) system can reduce cost by replacing building facade as construction material such as roofs, outer walls and windows as well as generating electricity. BIPV system should be applied at the early stage of architectural design. However, it is hard to decide whether using BIPV system or not for architects and builders who are not professional at BIPV system because performance of system is considerably influenced by types of module, installation position, installation methods and so on. It is also hard for experts because commercialized analytical program of photovoltaic systems is too complicated to use and domestic meteorological data is limited to partial areas. Therefore, we need evaluation program of BIPV system which can easily but accurately interpret generating performance and evaluate validity of BIPV system at the early stage of architectural design even for inexpert. Method: In this study, we collected meteorological data of domestic major region and analyzed generation characteristic of BIPV system by using PVsyst(commercialized software) in accordance with regions, types of solar module, place and methods of installation and so on. Based on this data, we developed performance evaluation program of BIPV system named BIPV-Pro, through multiple regression analysis and evaluated its validity. Result: When comparing predictive value of annual average PR and annual electricity production of BIPV-Pro an that of PVsyst, each of root mean square error was 0.01897 and 123.9.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.21 no.7
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• pp.715-725
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• 2010

Orthgonal Frequency Division Multiplexing(OFDM) system is effective for the high data rate transmission in the frequency selective fading channel. In this paper we propose PAPR(Peak to Average Power Ratio) reduction method of problem in OFDM system used Fuzzy theory that often control machine. This thesis proposes PAPR reducing method of OFDM system using Fuzzy theory. The advantages for using Fuzzy theory to reduce PAPR are that it is easy to manage the data and embody the hardware, and required smaller amount of operation. Firstly, we proposed simple algorithm that is reconstructed at receiver with transmitted overall PAPR which is reduced PAPR of sub-block using Fuzzy. Although there are some drawbacks that the operation of the system is increased comparing conventional OFDM system and it is needed to send the information about Fuzzy indivisually, it is assured that the performance of the system is enhanced for PAPR reducing. To evaluate the perfomance, the proposed search algorithm is compared with the proposed algorithm in terms of the complementary cumulative distribution function(CCDF) of the PAPR and the computational complexity. As a result of using the QPSK and 16QAM modulation, Fuzzy theory method is more an effective method of reducing 2.3 dB and 3.1 dB PAPR than exiting OFDM system when FFT size(N)=512, and oversampling=4 in the base PR of $10^{-5}$.

• Journal of the Korean Solar Energy Society
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• v.37 no.2
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• pp.35-45
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• 2017

The types of installation of the photovoltaic system applied to domestic residential buildings are classified as follows: Mounted modules with air circulation, semi-integrated modules with air duct behind, integrated modules with fully insulated back. In order to study generation characteristics of PV system, we verified the validity of interpretation program based on long-term measurement data of demonstration house installed in BAPV form and also analyzed the generation characteristics and performance of each installation type. The results are as follows. First, the RMSE of amount of generation and simulation according to annual daily insolation of demonstration system located in Daejeon was 0.98kWh and the range of relative error of monthly power generation was -5.8 to 3.1. Second, the average annual PR of mounted modules was 82%, semi-integrated modules 76.1% and integrated modules 71.9%. This differences were attributed to temperature loss. Third, the range of operating temperature of annual hourly photovoltaic modules was -6.5 to $61.0^{\circ}C$ for mounted modules, $-6.0{\sim}73.9^{\circ}C$ for semi-integrated modules and -5.5 to $88.9^{\circ}C$ for integrated modules. The temperature loss of each installation type was -14.0 to 16.1%, -13.8 to 21.9%, and -13.6 to 28.5%, respectively.

• Journal of the Korean Society of Propulsion Engineers
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• v.22 no.5
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• pp.66-72
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• 2018

A numerical study was conducted to investigate the performance characteristics of a STED with various pressure ratios (PRs) and cone shapes. Due to momentum loss, the pressure in vacuum chamber increased with cone angle for a PR of 75. Also, the STED is started between PRs of 36 and 37 in the case of a cone angle of $15^{\circ}$ and a blockage ratio (BR) of 15%. The results for various PRs and cone shapes are presented, and the optimal cone shape is found to have a cone angle of between $5{\sim}20^{\circ}$ and a BR of between 15~40%.

• Journal of Aquaculture
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• v.16 no.2
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• pp.104-109
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• 2003

The present study aims to evaluate protein and phosphorus availabilities of five different dietary protein sources during the 6-week feeding trial in juvenile olive flounder, Paralichthys olivaceus as determined by growth performance and phosphorus retention. Five diets containing blood meal (BM), poultry by-product (PBP), squid liver powder (SLP), feather meal (FM) and soybean meal (SM) were prepared by mixing a basal diet (BD) with one of five test ingredients at the ratio of 7 to 3. As a reference diet, BD contains three different protein sources such as white fish meal, casein and gelatin. After 2 weeks of the conditioning period, fish initially averaging 2.7$\pm$0.02g (mean$\pm$SD) were randomly distributed into each aquarium as a group of 30 fish reared in the recirculating system. Fish of triplicate groups were fed one of six experimental diets (BD+five test diet). After 6-week feeding trial, pro- tein efficency ratio (PER) of fish fed BM diet was the lowest in experiment groups. While fish fed PBP diet showed a significant higher PER as compared to the FM diet, and fish fed SLP diet and BD were a higher PER than did fish fed PBP diet. However, there was no significant difference in PER among fish fed SLP diet, BD and SM diet, and between SM diet and PBP diet. Phosphorus retention efficiency of bone (PR $E_{b}$) of fish fed BM diet was the lowest in all the diets, and fish fed FM diet showed a higher PE $R_{b}$ than fish fed BD and SM diet. However, there was no significant difference in PER among fish fed FM diet, SLP diet and PBP diet, and among SLP diet, PBP diet, SM diet and BD. These results indicate that SLP could be a suitable protein source for low pollution diets of olive flounder in the future fish feeds market. Furthermore, PBP and SM are available protein source to reduce P waste in the oliver flounder aquaculture with the use of proper mixture of other protein sources and more processing to improve protein availibility of these.ese.

• Journal of Communications and Networks
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• v.11 no.6
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• pp.589-598
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• 2009

In wireless sensor networks, a node that reports information gathered from adjacent assets should relay packets appropriately so that its location context is kept private, and thereby helping ensure the security of the assets that are being monitored. Unfortunately, existing routing methods that counter the local eavesdropping-based tracing deal with a single asset, and most of them suffer from the packet-delivery latency as they prefer to take a separate path of many hops for each packet being sent. In this paper, we propose a routing method, greedy perimeter stateless routing-based source-location privacy with crew size w (GSLP-w), that enhances location privacy of the packet-originating node (i.e., active source) in the presence of multiple assets. GSLP-w is a hybrid method, in which the next-hop node is chosen in one of four modes, namely greedy, random, perimeter, and retreat modes. Random forwarding brings the path diversity, while greedy forwarding refrains from taking an excessively long path and leads to convergence to the destination. Perimeter routing makes detours that avoid the nodes near assets so that they cannot be located by an adversary tracing up the route path. We study the performance of GSLP-w with respect to crew size w (the number of packets being sent per path) and the number of sources. GSLP-w is compared with phantom routing-single path (PR-SP), which is a notable routing method for source-location privacy and our simulation results show that improvements from the point of the ratio of safety period and delivery latency become significant as the number of source nodes increases.

• Journal of Korean Public Health Nursing
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• v.3 no.2
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• pp.77-108
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• 1989

The purpose of this study was to find out the present condition of clinical practice and to develop a scheme on the efficiency of clinical practice for nursing education in junior college of nursing in korea. This study was conducted by 2 sections. Ist section was to find out the present condition of clinical practice to 42 directors of nursing collegd and data were collected July 8 to September 30, 1988. 2nd section wat to develop a scheme on the efficiency of clinical practice for nursing education and subjects were nursing professors 258: and clinical nurses 223 in 42 junior nursing colleges their clinical settings in korea. So total subjects were 481. Data were collected july 8, 1988 to June 30, 1988 and were analysed to get the mean, standand deviation, frequency, percentage, t-test, x-test used by SPSS - pc. Major findings were as follows: 1. The present condition of clinical education in junior college of nursing in Korea. 1) 32 colleges (76.2%) were managed by a-yeas system. 2) 25 colleges (59.5%) were performed by individual practice for each subject. 3) 4 weeks interval between class education and clinical education was a major type among total colleges(36.6%, J5 colleges) 4) 30 colleges (71.4%) provided clinical education for all subjects that should be practiced. Nursing administration wes not practiced in 5 colleges (41.9%) among the remainder(12 colleges). The main cause that all practice subjects were not practiced was the lack or absence of suitable clinical settings(8 colleges. 66.7%) 5) 18 colleges (42.9%) responded that a clinical educator was, subject-charged professor. 6) 12 colleges (29.3%) responded that a clinical instructor was in charge of 6~10 students. 7) The evaluation ration ratio(professor to head nurse) by each evaluator was mostly 50% to 50 % and 60% to 40%, respectively 11 colleges(27.5%) The most common evaluation methods were evaluation by head nures, report, presence, conference (11 colleges, 27.5%) 8) The field carrier of professor was mostly 2 years (79 persons, 20.7%) and mean was 3.2 years. The education carrier of a professor was mostly over than 6 years (261 persons, 66.4%) and mean was 9.2 years. The charge hours per-week of a professor were mostly 16-18 hours (16 persons, 131.8%) 9) 34 colleges (82.9%) approved that clinical practice hour was class hour and 18 colleges (43.9 %) counted that 2 hours of clinical education equaled 1 hour of class education. 2. A study 'on the efficiency of clinical practice for nursing education. L) general characteristics of subjects were as follows: kung-sang province (145 persons, 30.5%), 30-34 years (190 persons, 39.8%), graduated degree (245 persons, 51.5%), 6-10 years of carrier (199 persons, 41.4%) were the majority. 2) suitable clinical setting was responded the systematic ward with responsible clinical educator by 210 persons(43.8%) The response by working field of subjects showed a significant difference (p< 0.01) 3) 259 subjects (54.0%) responded that the desirable qualfication of clinical instructor was 3-5 years of clinical experience with master degree or higher. 4) The mean score of desirable quality degree of clinical instructor was 3.43 professors, score (3.54) was significantly higher than clinical nurses' (3.28) (p<0.01) 412 subjects (86.0%) responded that the insufficient guality of instructor was improved by continuing to seek more new information in reference. 5) 196 subjects (41.4%) responded that desirable qualification of head nurse was more than 2 years of head position among 5 years of clinical experience. The response by working' field of subjects showed a significant difference (p<0.05) 6) The mean score of desirable quality degree of head nurse was 3.18 Clinical nurses' score(3.38) was significantly higher than professors' (3.01) (p<0.01) 419 subjects (87.8%) responded that the insufficient of head nurse was improved by continuing relationship with instructor and being responsible from planing of clinical education. 7) The mean score of performance level of the desirable clinical education guide incollege was 2.91 Professors' score (2.96) was significantly higher than clinical nurses' (2.84) (p<0.01) 340 subjects (71.1%) responded that the possible resolution for poor performance was the more specified syllabus of clinical education and the satisfiable orientation for students. 8) The mean score of performance level of the desirable clinical education guide in hospital was 3.03 9) 141 subjects (29.6%) responded that the desirable clinical evaluator was the group of professor, head nurse, staff nurse. Response by working field of subjects was a significant difference (p< 0.05) 10) The mean score of performance level of the evaluation content needed in clinical education was 3.50 Clinical nurses' score (3.56) was significantly higher than professors' (3.45) (p<0.01) 11) 433 subjects (90.2%) responded that6 desirable evaluation method for clinical education was the presence. 12) The mean score of performance level about how personal difference among clinical educators was minimized was 2.89 and response by working field of subjects was not significant. The cause of poor performance was too much workload at clinical settings and too many students st colleges by 386 subjects (81.1%).