• Proceedings of the Korean Institute of Building Construction Conference
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• 2023.05a
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• pp.365-366
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• 2023

The purpose of this study is to prevent dispute due to change orders in construction projects and to handle change orders smoothly. For this purpose, this study analyzed arbitration cases caused by change order handled by the Korea Commercial Arbitration Board. Based on this, dispute factors were analyzed and change order management factors and management plans were presented. Change order management factors were derived from responsibility, contract, design, process, construction cost, and schedule management, and a detailed management plan according to the relevant factor was presented.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2007.11a
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• pp.89-90
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• 2007

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.49 no.3
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• pp.238-249
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• 2013

Species composition and seasonal variation of aquatic organism in the marine ranchig ground of Taean, Korea were investigated using shrimp beam trawl from January to December 2010. A total of 99 species, $5,355,816ind./km^2$ and $84,697kg/km^2$ of aquatic organism were collected. Among them, fish include 9 orders 33 families 54 species, crustaceans include 2 orders 15 families 30 species, cephalopods consist of 3 orders 4 families 5 species, gastropods include 2 orders 3 families 4 species, echinoidea sp. include 1 order 2 families 2 species, bivalves were composed of 2 orders 2 families 2 species, and holothuroids include 1 family 1 order. According to the dominants by month, Palaemon gravieri was dominant in January, Cynoglossus joyneri was dominant in February, March, and June, and Hexagrammos otakii was dominant, in July. And Oratosquilla oratoria was dominant echinoidea sp. was dominant in April, May, and August and in September, October, November, and December. Cluster analysis based on species composition of the 38 most common species showed that the species were separated into 5 different groups. Group A was composed of species which were abundant in spring and summer, group B was composed of year-round residents, and group C was composed of species which were abundant in autumn.

• Korean Journal of Construction Engineering and Management
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• v.14 no.5
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• pp.55-64
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• 2013

The complexity of constructing medical institutions is higher than that of general buildings, and many change orders in the design and defect repairs in the construction phase are required due to strict government regulations. The priority control of constructions and impact factors of medical institutions were analyzed in this study, and difficulties in the control in the design and construction phase were identified. First, the priority management factors that were identified were as follows: architecture, facilities, and electricity. Second, 1) priority management in constructions and factors resulting in change orders and 2) priority management in constructions involving defect repair were analyzed. Third, the importance recognized by the construction managers were analyzed. The priority management in constructions and factors that were recognized by the construction manager were deducted as having low importance, although there were many change orders and defects. The work of finishing, wall building, joining, office automation and communication function, and lighting were analyzed in the design phase, and waste, the office automation and communication function, ceilings, contamination control, and plumbing were analyzed in the construction phase. The results showed that there will be a decrease in change orders and defects if the concentration of the manager was elevated and priorities were managed.

• The Korean Journal of Mycology
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• v.42 no.4
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• pp.289-305
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• 2014

This survey was conducted in order to clarify the species diversity and distribution of mushrooms at Worldcup Park in Seoul, from May to November 2010 and 2014. In the survey, a total of 98 taxa, 98 species, 86 genera, 38 families, 12 orders, three classes, and two phyla were identified. A total of 250 specimens of Mushrooms were collected from Pyonghwa Park and 63 species, 71 genera, 36 families, 13 orders, three classes, and two phyla were identified. Coprinus atramentarius and Psathyrella candolleana were high in frequency, as ten times and nine times, respectively. In Noeul Park, 102 specimens were collected, 41 species, 42 genera, 19 families, 19 orders, two classes, and two phyla were identified. In Noeul Park mostly layed with lawn, Agrocybe semiorbicularis and Agaricus campestris were high in frequency, as ten times and nine times, respectively. There were no mushrooms in succession during three years. In Haneul Park, a total of 128 specimens of mushrooms were collected. 49 species, 57 genera, 30 families, 11 orders, three classes, and two phyla were identified. Agrocybe semiorbicularis and Phallus rugulosus were high in frequency, as four times. In Nanjicheon Park, a total of 68 specimens of mushrooms were collected. 31 species, 34 genera, 30 families, nine orders, one class, and one phylum were identified. Coprinus atramentarius and Psathyrella velutina were high in frequency, as three times. Investigation on the diversity of mushrooms at the Worldcup Park, piled up with the city's waste, will be of the great significance in the aspect of the ecological change. All specimens examined in this work are preserved in HCCN (Herbarium Conservation Center of National Academy of Agricultural Science).

• Journal of Electrical Engineering and Technology
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• v.10 no.1
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• pp.261-270
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• 2015

In this paper, the Optimal Harmonic Stepped Waveform (OHSW) method is proposed in order to eliminate the selective harmonic orders available at the output of cascaded multilevel inverter (CMLI) fed by solar photovoltaic (SPV). This technique is used to solve the harmonic elimination equations based on stepped waveform analysis in order to obtain the optimal switching angles which in turn reduce the Total Harmonic Distortion (THD). The OHSW method considers the output voltage waveform as four equal symmetries in each half cycle. In the proposed method, a solar fed fifteen level cascaded multilevel is considered where the magnitude of six numbers of harmonic orders is reduced. A programmable pulse generator is developed to carry the switching angles directly to the semiconductor switches obtained as a result of OHSW analysis. Simulations are carried out in MATLAB/Simulink in which a separate model is developed for solar photovoltaic which serves as the input for cascaded multilevel inverter. A 3kWp solar plant with multilevel inverter system is implemented in hardware to show the effectiveness of the proposed system. Based on the observation the OHSW method provides the reduced THD thereby improving power quality in renewable energy applications.

• Journal of applied mathematics & informatics
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• v.5 no.2
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• pp.373-382
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• 1998

Most of the works in Time Series Analysis are based on the Auto Regressive Integrated Moving Average (ARIMA) models presented by Box and Jeckins(1976). If the data exhibits no ap-parent deviation from stationarity and if it has rapidly decreasing autocorrelation function then a suitable ARIMA(p,q) model is fit to the given data. Selection of the orders of p and q is one of the crucial steps in Time Series Analysis. Most of the methods to determine p and q are based on the autocorrelation function and partial autocor-relation function as suggested by Box and Jenkins (1976). many new techniques have emerged in the literature and it is found that most of them are over very little use in determining the orders of p and q when both of them are non-zero. The Durbin-Levinson algorithm and Innovation algorithm (Brockwell and Davis 1987) are used as recur-sive methods for computing best linear predictors in an ARMA(p,q)model. These algorithms are modified to yield an effective method for ARMA model identification so that the values of order p and q can be determined from them. The new method is developed and its validity and usefulness is illustrated by many theoretical examples. This method can also be applied to an real world data.

• Korean Journal of Ecology and Environment
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• v.53 no.1
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• pp.22-30
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• 2020

In this study, we investigated the relationships between benthic macroinvertebrate assemblages and various environmental factors in Iancheon (NIA) and Bukcheon (NBC) streams, Korea. We collected benthic macroinvertebrates and 33 environmental factors in April 2017 at 9 sites (5 sites in NIA and 4 sites in NBC). We identified 93 species(5 phyla, 9 classes, 16 orders, and 53 families) and 69 species(5 phyla, 9 classes, 17 orders, and 47 families) in NIA and NBC streams, respectively. Considering benthic macroinvertebrate index (BMI), NIA (88.2) and NBC (80.2) streams were in "very good" status. Upstream areas showed the highest scores, 95.5 (NIA1) and 94.2 (NBC1), whereas BMI score was the lowest in downstream areas of both streams, especially in NBC4 (51.0 "bad" status). Cluster analysis and non-metric multidimensional scaling analysis represented the differences of benthic macroinvertebrate assemblages according to spatial and anthropogenic gradients. Our findings provide reference data and highlight the need for the continued monitoring to maintain the good status and manage macroinvertebrate diversity in these two streams, in Sangju-si, Korea.

• Journal of the Korea Institute of Building Construction
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• v.13 no.2
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• pp.112-121
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• 2013

Korean overseas construction has been on the rise, and exceeded the 2011 goal of $50 billion by securing $59.1 billion in orders. However, these orders were heavily concentrated in the Middle East (50%) and plant construction contracts (75%). This study suggests that, to maintain growth in foreign markets, Korea construction companies should enter into the high value-added investment development business and aggressively seek ways to diversify their regions of activity and construction types. To secure the entry of Korean construction companies into lucrative markets and better understand the competitive factors facing Korean construction concerns, a survey of the literature and focus group discussions targeting relevant experts were carried out. From those efforts, a list of 44 competitive factors crucial to entering and competing in the international investment development business was developed. Survey responses were analyzed by applying IPA. The results revealed that while Korean concerns compete well in engineering/technical capabilities, maintaining a cooperative relationship with contractors, and warranty/after sales service capabilities, their ability to obtain business information on the target country, to form private/public cooperative systems, and to build international human networks require immediate improvement.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.7A
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• pp.986-993
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• 2000

In this paper, we analyze transmission characteristics of ultrashort laser pulses using the properties of high-order pulses which are systematically obtained following their orders. The high-order pulses are easily derived from a modified PRS system model. But we make clear they are very useful to cover wider area and to show more accurate transmission characteristics of ultrashort pulses than Gaussian or Sech pulse approximations used conventionally. These are based on the fact that the spectra and bandwidths of the high-order pulses are geautifully related to their orders. First modifying the generalized PRS system model, we propose a new model for deriving any type of high-order pulse. And we offer a novel analysis method of ultrashort pulse transmission varying the order of the pulse from n=1 to n=100, we obtain spectra of ultrashort pulses with 1(ps)∼150(fs) FWHM's, which are widely used in optical pulse communications. One-step further, we derive PSD's of their pulse-tr ins when they are applied to Unipolar signaling scheme. These PSD's are decided in the range of possible pulse intervals. All of these results are not only coincided with some conventional experimental works but will be applied to any pioneering ultrashort pulse in the future.