• Journal of Korean Society of Transportation
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• v.24 no.3 s.89
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• pp.177-187
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• 2006

It is known that over one million car navigation devices are being currently used in Korea. Most. if not all, route guidance systems, however, Provide only one "best" route to users, not providing any options for various types of users to select. The current practice dose not consider each individual's different preferences. These days, a vast amount of information became available due to the rapid development in information processing technology. Thus, users Prefer choices to be given and like to select the one that suits him/her the "best" among available information. To provide such options in this Paper, we developed an algorithm that provides alternative routes that may not the "least cost" ones, but ones that are close to the "least cost" routes for users to select. The algorithm developed and introduced in the paper utilizes a link-based search method, rather than the traditional node-based search method. The link-based algorithm can still utilize the existing transportation network without any modifications, and yet enables to provide flexible route guidance to meet the various needs of users by allowing transfer to other modes and/or restricting left turns. The algorithm developed has been applied to a toy network and demonstrated successful implementation of the multi-path search algorithm for multi-purpose activities.

• The Journal of the Korea Contents Association
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• v.19 no.4
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• pp.403-412
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• 2019

There has been a lively debate between self-employed and wage workers on the speed of minimum wage hikes. Minimum wage is a redistributive policy that evokes confrontation and conflict whereby individuals' views on the policy coincide with their material self-interest. With this in mind, the researcher analyzed whether an individual's labor market status was explanatory to his/her view on the speed of minimum wage hike. Moreover, in light of the likelihood that the varying degree to which self-employed can afford minimum wage hike affects their differential preferences for the policy, the researcher attempted to identify whether there was a moderation effect of income class on the relationship. In the actual analysis, the researcher investigated employment policy survey dataset using a multinomial logit model. The results suggest that, among self-employed, 'gradual increase' and 'rapid increase' of minimum wages are less preferred $vis-{\grave{a}}-vis$ 'minimal increase,' which is the reference. As to the moderation effect, when a self-employed has a middle-income class status, his/her negative preference for the policy is likely to be attenuated. One implication of this study is that subsidizing self-employed small business owners, who are most dissatisfied with the current speed at which minimum wages rise, would be an effective prescription on reducing social conflicts.

• Environmental and Resource Economics Review
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• v.6 no.1
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• pp.129-152
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• 1996

본 연구는 다양한 변수에 따라 달라지는 환경산업의 경제성을 비교평가히는 모델을 개발한 것이다. 최근 환경산업으로 부각되고 있는 지역난방과 개별가스난방사업을 사례로 모델을 실증적으로 적용하여 시뮬레이션하였다. 열병합발전과 보조보일러 및 쓰레기 소각로로 구성된 지역난방시스템과 소각로와 개별 가스보일러로 구성된 개별난방시스템을 각각 최적화하고 최저비용을 구하여 비교한 것이다. 분석대상에 쓰레기소각로을 첨가함으로써 매립에서 소각으로 바뀌는 쓰레기정책을 반영하였으나 소각로 규모는 사전에 열공급과는 무관하게 결정되므로 다른 시스템과 연계하여 최적화 하지 않고 600톤/일의 규모로 정하여 분석하였다. 최적화하는 경우는 훨씬 규모가 줄어드는 것으로 나타났다. 국가경제적인 측면에서 다양한 난방방식에 따른 규모별, 열원별, 지역별(기후별), 사용연료별로 경제성과 환경성을 비교평가함으로써 변수의 변화에 따른 합리적인 난방방식 및 사용연료를 선택하도록 하였다. 환경배출량도 동시에 비교하였으나 시나리오 간에 크게 차이가 나지않아 비교에는 포함시키지 않았다. 이 모델은 난방사업 뿐만 아니라 갈등이 예상되는 다른 환경산업들을 평가하는데도 용이하게 활용될 수 있도록 GAUSS프로그램으로 개발되어 있다.

• Economic Analysis
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• v.26 no.1
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• pp.1-33
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• 2020

Recent discussions about a minimum wage increase (MWI) and its influence on the economy have mainly focused on the quantitative aspects, such as labor costs and employment. However, concerning the qualitative aspects, an MWI could have positive effects by enhancing firm productivity and crowding out marginal firms from the market. These positive effects of an MWI can offset, to some extent, its potential negative effects - increasing labor costs and decreasing employment, among others. In this regard we empirically examine the impact of an MWI on firm productivity (total factor productivity). Using firm level panel data from the manufacturing industry in Korea, we calculate the influence rates of a minimum wage by sector and by firm size (number of workers), and analyze its effects on firm productivity. In particular, the production functions of the firms are estimated by taking into account endogeneity among the input factors, in order to resolve the drawbacks of existing studies - underestimating the capital factor coefficient and overestimating the labor factor coefficient. This study finds that the influences of an MWI on wages, employment, and productivity are substantially different across sectors and firm sizes. While an MWI has shown to have positive influences on productivity growth in the manufacturing industry as a whole, each sector demonstrates a different direction of effect, and the degree of productivity change also varies by sector. The impacts of an MWI on firm productivity are generally estimated to be more negative for smaller firms, but in some sectors the effects are found to be positive. In addition, the wage increases resulting from an MWI seem to cause a productivity enhancement across all sectors in the manufacturing industry. The policy implications of this study are as follows. Considering the empirical findings that an MWI causes an increase in productivity in many sectors of the manufacturing industry, it would be desirable to take into consideration not only the negative side effects but also the positive effects of an MWI when designing any future minimum wage policy. Moreover, in spite of there being a uniform minimum wage, this study finds that the diverse influence rates of a minimum wage across firms have different impacts on wages, employment, and productivity across sectors or firm size. This finding could be conducive to discussions about differentiation among minimum wage schemes by sector or firm size.

• Journal of Korean Society of Transportation
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• v.24 no.6 s.92
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• pp.65-74
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• 2006

The costs of owning car are accepted as a subscription fee for participating in car-oriented society and only direct out-of-pocket costs of driving are mostly considered, so that the efficient location with better accessibility to service facilities is often under-appreciated. The purpose of this study is to explore the impact of accessibility to public transport and other service facilities on travel demand and transportation cost of household. The residential areas in Hamburg are categorized into 8 types according to level of public transport and other service facilities. The costs of owning and operating car in each residential area are calculated on the base of the household automobile ownership and usage analysed through the actual survey The result of this analysis shows that the transportation cost of household is decreased In proportion to the level of Public transport and other service facilities. This analysis finds the structure of residential area, which economize energy consume and makes household actual transportation cost saying Possible. The result of the analysis can be used as a tool for influencing home locaion choice towards Public transportaion corridors.

• Journal of Korea Society of Industrial Information Systems
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• v.19 no.5
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• pp.25-31
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• 2014

Bioelectrical Impedance Analysis(BIA) is a widely used method for estimating body composition changes which is a non-invasive, inexpensive, safety and reproductive method. We studied the bioimpedance change and the distinction of blood pressure according to body posture and conducted three kinds of experiments: the real-time bioimpedance measurement, the simulation using equivalent circuit model and the blood pressure measurement. Bioimpedance is measured during 4 minutes at the multi-frequency(1 kHz, 10 kHz, 20 kHz, 50 kHz, 70 kHz, 100 kHz). From the experiment results, the changes in body postures result in changes of resistance and reactance, with an average rapid increase of body impedance when going from standing, sitting to supine. Specially, the laying resistance on average was 16.49% higher than supine resistance at 50 kHz and the laying reactance measurement was also 26.05% higher than sitting reactance at 1 kHz. Blood pressure in standing posture was higher than those in other postures both in maximum($125.14{\pm}12.30$) and in minimum($75.57{\pm}10.31$). The results of BIA and blood pressure in this study will be contributed to the research on acute illness, extreme fat, and body shape abnormalities.

• Land and Housing Review
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• v.14 no.3
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• pp.17-36
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• 2023

This research aims to investigate the socio-demographic, financial, and housing statuses of young married couples in Chonsei housing and to analyze the determinants of their residential environment quality and housing expenditure in four districts - Seoul and Gyeonggi-Incheon Area(GIA) of the Seoul Metropolitan Area(SMA), and metropolises and non-metropolises of non-SMA. From the 2020 Korean Housing Survey(KHS), this cross-sectional analysis examined a sample of 691 households, and the findings revealed that most were headed by college-educated, salaried male workers aged 31 years old. While childless dual-earner couples were common in Seoul, single-income families of three were prevalent in non-SMA. The financial status of the couples in Seoul was a lot better than in the other three areas, particularly much higher in Chonsei deposit and total asset value. Further, many lived in a three-bedroom apartment unit sized 60m² and bigger, using a Chonsei loan. Regardless of areas, almost all the households spent a very low portion of their living expenses and income on housing costs. However, dual-earner families positively increased borrowing capacity, which improves the household's financial position that is likely to lead to equity increment in a volatile asset market in the long run. The statistical results indicated that residential environment assessment was influenced by neighborhood quality and housing expenditure was affected by housing size in Seoul, urban amenities in GIA and householder's gender in non-metropolises. Thus, this research proposes that strong measures be considered to mitigate housing inequality embedded in geographical and socio-economic disparities.

• Resources Recycling
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• v.28 no.6
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• pp.26-35
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• 2019

This study aims to introduce and economical review on the possibilities of rare earth elements(REEs) recovery from coal ashes and the analysis of economical evaluation factors based on the data for securing domestic rare earth elements. The cut-off grade of REEs on recovering from coal ash was confirmed to be 1,000 ppm on total rare earth oxides(TREO) basis, and while the economic value of coal ash changed with contents and specific elements of rare earth elements. This shall be resulted in the price differences of rare earth elements required by the current industry, and it probably varies depending on the future demand of rare earth components. For developing of commercial recovery technology on REEs in coal ashes, many researches have been carried out by various analyzing methods, such as evaluation of holding value of REEs in ashes, assessment between supply and demand of industry, comparison of investment and its profitability for the REEs's production from coal ashes, and so on. Although these methods have been suggested, its recovery system with economical feasibility could not been confirmed up to present. In this reason, the process design of recovering REEs from coal ash shall be researched continuously to solve the problems of the global rare earth market. And also these researches shall be conducted actively in Korea for the purpose of securing the REEs resources and their recovering technologies.

• Journal of the Korean Society for Railway
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• v.13 no.1
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• pp.71-77
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• 2010

It is increasing annually that the cost for bridge Maintenance Repair & Rehabilitation (MR&R) in developed countries. Based on Intelligent Technology, Bridge Management System (BMS) is developed for optimization of Life Cycle Cost (LCC) and reliability to predict long-term bridge deteriorations. However, such data are very limited amongst all the known bridge agencies, making it difficult to reliably predict future structural performances. To alleviate this problem, an Artificial Neural Network (ANN) based Backward Prediction Model (BPM) for generating missing historical condition ratings has been developed. Its reliability has been verified using existing condition ratings from the Maryland Department of Transportation, USA. The function of the BPM is to establish the correlations between the known condition ratings and such non-bridge factors as climate and traffic volumes, which can then be used to obtain the bridge condition ratings of the missing years. Since the non-bridge factors used in the BPM can influence the variation of the bridge condition ratings, well-selected non-bridge factors are critical for the BPM to function effectively based on the minimized discrepancy rate between the BPM prediction result and existing data (deck; 6.68%, superstructure; 6.61%, substructure; 7.52%). This research is on the generation of usable historical data using Artificial Intelligence techniques to reliably predict future bridge deterioration. The outcomes (Long-term Bridge deterioration Prediction) will help bridge authorities to effectively plan maintenance strategies for obtaining the maximum benefit with limited funds.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.45 no.6
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• pp.382-386
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• 2000

This study was conducted to know the optimum conditions for overwinter culture of sweetpotato stems in PE film house. The stems will be used as transplant shoots in the next year instead of sprouts produced from storage roots. Sweetpotato stems were cut at field on harvest season and planted in PE film house under three different conditions of PE film mulching, tunnel, or mulching plus tunnel in comparison with the non-treatment of PE film on October 10 and November 10. The survival rate of sweetpotato stems, which was evaluated on April 10 after overwinter, was higher in the treatment planted on October 10 than that on November 10, and with PE film treatments, it was higher in tunnel or mulching plus tunnel than that of the non-treatment of PE film. The survival rate of sweetpotato stems to planting densities was 95-96% in 10$\times$2cm (333 stems/$m^2$) or in 10$\times$4cm (250 stems/$m^2$) when compared with 10$\times$2cm (500 stems/$m^2$). The survival rate under low temperature showed 95% until 20 days at 5$\pm$1$^{\circ}C$, and 0% within 5 days at 2$\pm$1$^{\circ}C$. From these results, it was concluded that there were optimum conditions that cutting time is middle October, planting density is 10$\times$3cm, and minimum maintenance temperature is 5$^{\circ}C$ in growing conditions of sweetpotato stems. Root yield produced by trans-planting shoots using the stems was similar to yield by shoots produced from roots, and the survival rate was not different among varieties.