• Journal of Korean Society for Atmospheric Environment
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• v.21 no.E1
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• pp.1-11
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• 2005

The concentration levels of gaseous elemental mercury (GEM) in ambient air have been investigated from a monitoring station located in Yang Jae district of Seoul, Korea for a long-term period covering 1997 through 2002. The mean concentration of Hg, if computed based on its hourly measurement data for this six-year period, was $5.32\pm3.53 ng m^{-3} (N = 27,170)$. The inspection of the diurnal distribution patterns indicated the presence of notably high concentration levels during nighttime relative to daytime (e.g., the mean hourly value as high as $9 ng m^{-3}$ in winter nighttime). When divided seasonally, the highest mean of $6.12 ng m^{-3}$ was also observed during winter followed by spring, fall, and summer. The results of our analysis confirmed the relative dominance of winter (seasonally) or nighttime (diurnally), while exhibiting a complicated trend on a long-term basis. Examination of our data over a different temporal scale consistently indicated that dynamic changes in Hg concentrations occurred through time in line with changes in the strength and diversity of the source processes. It is thus acknowledged that the presence of unusually high Hg levels is the consequence of intense man-made activities, while such signatures can vary in a competitive manner.

• Journal of the Korea institute for structural maintenance and inspection
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• v.15 no.5
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• pp.113-123
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• 2011

LCC analysis is a method that coordinates with function evaluation for value improvement, rather than a separate one for cost evaluation. Although its accuracy is rising, materials and structural types developed or applied relatively recently have yet to obtain a sufficient maintenance profile DB, inducing reliability to reduce from difficulties in estimating maintenance records. Based on the above mentioned background, this paper presents the LCC methodology of coordinating functional intensification matters with cost for analysis on alternatives with difficulties in setting maintenance profile. Recently, steel plate bridge deck pavements are faced with problems such as plastic deformation due to the increase in heavy vehicles and traffic, promoting the development of a new compound pavement. This paper execute LCC analysis by mentioning case studies of SMA, Guss and PSMA pavements to include performance scale compared between alternatives as relative evaluation coefficients into the maintenance profile.

• Journal of Veterinary Clinics
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• v.36 no.1
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• pp.15-22
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• 2019

Highly pathogenic avian influenza (HPAI) is among the top infectious disease priorities in Korea and the leading cause of economic loss in relevant poultry industry. An understanding of the spatial epidemiology of HPAI outbreak is essential in assessing and managing the risk of the infection. Though previous studies have reported the majority of outbreaks occurred clustered in what are preferred to as densely populated poultry regions, especially in southwest coast of Korea, little is known about the spatial distribution of risk areas vulnerable to HPAI occurrence based on geographic information system (GIS). The main aim of the present study was to develop a GIS-based risk index model for defining potential high-risk areas of HPAI outbreaks and to explore spatial distribution in relative risk index for each 252 Si-Gun-Gu (administrative unit) in Korea. The risk index was derived incorporating seven GIS database associated with risk factors of HPAI in a standardized five-score scale. Scale 1 and 5 for each database represent the lowest and the highest risk of HPAI respectively. Our model showed that Jeollabuk-do, Chungcheongnam-do, Jeollanam-do and Chungcheongbuk-do regions will have the highest relative risk from HPAI. Areas with risk index value over 4.0 were Naju, Jeongeup, Anseong, Cheonan, Kochang, Iksan, Kyeongju and Kimje, indicating that Korea is at risk of HPAI introduction. Management and control of HPAI becomes difficult once the virus are established in domestic poultry populations; therefore, early detection and development of nationwide monitoring system through targeted surveillance of high-risk spots are priorities for preventing the future outbreaks.

• Geomechanics and Engineering
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• v.17 no.1
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• pp.81-95
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• 2019

Due to the importance of soil reinforcement using geotextiles in geotechnical engineering, study and investigation into long-term performance, design life and survivability of geotextiles, especially due to installation damage are necessary and will affect their economy. During installation, spreading and compaction of backfill materials, geotextiles may encounter severe stresses which can be higher than they will experience in-service. This paper aims to investigate the installation damage of geotextiles, in order to obtain a good approach to the estimation of the material's strength reduction factor. A series of full-scale tests were conducted to simulate the installation process. The study includes four deliberately poorly-graded backfill materials, two kinds of subgrades with different CBR values, three nonwoven needle-punched geotextiles of classes 1, 2 and 3 (according to AASHTO M288-08) and two different relative densities for the backfill materials. Also, to determine how well or how poorly the geotextiles tolerated the imposed construction stresses, grab tensile tests and visual inspections were carried out on geotextile specimens (before and after installation). Visual inspections of the geotextiles revealed sedimentation of fine-grained particles in all specimens and local stretching of geotextiles by larger soil particles which exerted some damage. A regression model is proposed to reliably predict the installation damage reduction factor. The results, obtained by grab tensile tests and via the proposed models, indicated that the strength reduction factor due to installation damage was reduced as the median grain size and relative density of the backfill decreases, stress transferred to the geotextiles' level decreases and as the as-received grab tensile strength of geotextile and the subgrades' CBR value increase.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.12 no.2
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• pp.125-136
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• 2017

This study focuses on a relative efficiency of 109 operating food companies out of 22 regions in Jeollanam-do. The relative efficiency has been analyzed by 5 input factors(capital, number of employees, annual labor costs, raw material purchase, and site area) and 2 output factors(annual exports and annual production of the companies in Jeollanam-do). This study suggests efficient companies which inefficient companies can benchmark to improve their system in short-mid-long term in phases. The main result of empirical analysis are as follows: Firstly, according to the Traditioanl DEA analysis, 7 companies out of 109 DMU indicate the optimal production scale in score 1 of CCR efficiency value, BCC efficiency value, and scale efficiency value. Secondly, a result from the Tier 1 step of inefficient companies by Post-DEA suggests that it would be better to apply each Tier step to the proper stage of the worst 5 inefficient companies such as Tier 3 step(short-term benchmark)${\rightarrow}$Tier 2 step(mid-term benchmark)${\rightarrow}$Tier 1 step(long-term benchmark) in step. This study expects that the result of the study can reduce the trial and error in inefficient part, lead to improvement, and have a big help in food exporting industry in the end.

• Nutrition Research and Practice
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• v.6 no.6
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• pp.542-550
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• 2012

This pilot study was performed to produce data of the Children's Dietary Life Safety (CDLS) Index which is required by the Special Act on Safety Management of Children's Dietary Life and to evaluate the CDLS Index for 7 metropolitan cities and 9 provinces in Korea. To calculate the CDLS Index score, data regarding the evaluation indicators in the children's food safety domain and children's nutrition safety domain were collected from the local governments in 2009. For data regarding the indicators in the children's perception & practice domain, a survey was conducted on 2,400 5th grade children selected by stratified sampling in 16 local areas. Relative scores of indicators in each domain were calculated using the data provided by local governments and the survey, the weights are applied on relative scores, and then the CDLS Index scores of local governments were produced by adding scores of the 3 domains. The national average scores of the food safety domain, the nutrition safety domain and the perception and practice domain were 23.74 (14.67-26.50 on a 40-point scale), 16.65 (12.25-19.60 on a 40-point scale), and 14.88 (14.16-15.30 on a 20-point scale), respectively. The national average score of the CDLS Index which was produced by adding the scores of the three domains was 55.27 ranging 46.44-58.94 among local governments. The CDLS Index scores produced in this study may provide the motivation for comparing relative accomplishment and for actively achieving the goals through establishment of the target value by local governments. Also, it can be used as useful data for the establishment and improvement of children's dietary life safety policy at the national level.

• Journal of the Korean Society of Marine Environment & Safety
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• v.28 no.1
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• pp.91-99
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• 2022

The shipping industry is a service industry that operates its business by transporting cargo on ships and receiving freight. Therefore, large-scale capital investment is required for ship operation, and if the value of the ship is uncertain, the risk of shipping management increases. This study aims to identify the factors affecting changes in ship value and to analyze the importance of each variable. To achieve the goal, the factors affecting changes in ship value were identified and structured using the techniques of text mining and topic modeling, and classified into three main factors and 12 sub-factors. This study used AHP analysis to examine the relative importance of each factor. Results indicated that the main factor influencing the change in the vessel value was the shipping factor, followed by the investment factor and the environment factor. Other auxiliary factors that substantially affect the ship value include the volatility of the shipping market and of shipping freight.

• Journal of Korea Trade
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• v.27 no.4
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• pp.1-18
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• 2023

Purpose - The purpose of this paper is to study how flexibility and mutuality in determining trade terms impact logistics efficiency in the context of relational theory. Additionally, the effect of relational contracts on logistical efficiency relative to the value of the goods being traded is investigated. Design/methodology - According to the relational contract theory, we developed 17 factors utilizing a 7-point Likert scale to measure variables related to flexibility, mutuality, logistics efficiency, and the added value of goods. The survey occurred over four months, and was distributed directly, and via email, phone, and online Google surveys. A total of 403 surveys were collected out of 1,800 distributed, and 380 were analyzed. The principal respondents were import/export companies and members of the Korea International Trade Association and the Korea Small and Medium Business Export-Import Association. The collected data were analyzed using frequency analysis, exploratory factor analysis, and correlation analysis using SPSS ver. 26.0 statistical software, and hypothesis test results were derived using Process Macro ver. 3.5. Findings - This study provides evidence that negotiation flexibility for trade terms affects the efficiency of the logistics process, and the mutuality of such arrangements is shown to be associated with the flexibility and efficiency of logistics processes. Additionally, it has been established that companies whose trade goods possess a low degree of added value may experience increased efficiency in logistics operations if they agree to trade terms that are both flexible and mutually beneficial with their counterparts. Originality/value - This study suggests that in an environment of rapidly shifting global logistics and unpredictable related costs, trade companies may be able to improve logistics efficiency by establishing flexible, mutually beneficial trade terms when entering into contracts. Furthermore, it is suggested that companies dealing in low-value-added products may improve the logistical performance of approaching trade from a perspective of relational contracts.

• The Journal of the Korea Contents Association
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• v.9 no.5
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• pp.224-229
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• 2009

This study measures the relative efficiency and productivity change of the Korean Non-Life Insurance Firms using DEA model and Malmquist Index for 2004-2007. The main results of this study can by summarized as follows. First, in case of efficiency of CCR for 2004-2007, the number of efficient firms(CCR value is one) are one firm, one firm, one firm, one firm respectively. Second, in case of efficiency of BCC for 2004-2007, the number of efficient firms(BCC value is one) are five firms, five firms, six firms, six firms respectively. Third, In case of return to scale for 2004-2007, DRS are five firms, DRS are five firms, DRS are six firms, DRS are six firms respectively, Fourth, Malmquist Index representing productivity change for 2004-2007 are 0.99 in 2004-2005, 1.04 in 2005-2006, 1.06 in 2006-2007.

• Journal of Oral Medicine and Pain
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• v.48 no.3
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• pp.106-111
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• 2023

Purpose: In this study, we evaluate the potential of the relative ratio of capsular width (RCW) between the affected side (Aff) and non-affected side (Non-aff) in patients with temporomandibular joint (TMJ) arthralgia. We assessed whether RCW may hold greater diagnostic significance than the objective capsular width (CW) reported in previous studies when diagnosing arthralgia using ultrasonography (US). Methods: Forty-nine patients were assessed using US, excluding four patients with bilateral arthralgia. The patients were divided into two groups: 40 with unilateral arthralgia (UA), and nine without arthralgia (NA). We measured CW and masseter muscle thickness using US. Moreover, we employed RCW to analyze the variances between the groups. The numerical rating scale (NRS) and RCW were compared before and after dexamethasone injection in 10 patients who underwent follow-up evaluations. Results: Within the UA group, CW on the Aff was found to be significantly larger compared to the Non-aff (p<0.001). Additionally, RCW in the UA group was greater than that in the NA group (p<0.01). Furthermore, after dexamethasone injection, a reduction in the NRS and RCW values was observed in the 10 patients who were followed up. Conclusions: While previous studies have suggested a link between arthralgia and TMJ effusion, making CW a possible indirect diagnostic indicator for arthralgia, our findings propose that RCW could hold more diagnostic value than objective CW. However, additional studies are required to standardize the protocols for interpreting US results and determining the cutoff value of RCW in diagnosing TMJ arthralgia.