• KDI Journal of Economic Policy
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• v.34 no.3
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• pp.133-186
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• 2012

This paper analyzes the effectiveness of social networks in finding jobs and estimates the value of job search network using the Korean Laber and Income Panel Study (KLIPS) dataset and utilizing the Difference-in-Difference Propensity Score Matching (PSM) methodology (Heckman et al., 1997). While the wide use of social networks in the Korean labor market is often perceived as 'nepotism,' this study confirms that social networks, by serving as an effective information transmitter between job search and recruitment, make a significant contribution to improving the adequacy of job matching in the domestic labor market. In order to verify the effectiveness of using social networks for getting jobs, this study looks into the cases of labor turnover using social networks and also not using it. In the aspect of individual satisfaction improvement relating to workplace and job duties, both cases of turnover turn out to experience an increased satisfaction by 2~3 points (on a 100-score scale). Meanwhile, as for the educational and technical adequacy improvement, no positive effects are found in the case of turnover without social networks, whereas the educational and technical adequacy improvement turns out to increase by 2.13 and 2.52 points, respectively, in the case of turnover using social networks. The effect of income increase through turnover using social networks registered 40,074 Korean won per month (as of 2010), which can be considered as the result from the improved educational and technical adequacy. Of all things being considered, the value of job search network per wage worker in the Korean society is estimated to be 18.72 million won in terms of life-cycle wage improvement, and 758.2 scores in terms of the improvement of working life satisfaction. Provided that the cash value of satisfaction score 1 is equivalent to 'n' times 10,000 won, the aggregate value of job search network is estimated to be 18.72+7.582n million won, which means the total amount of costs that a wage worker in the Korean society willingly pays to maintain and manage job networks for lifetime.

• Applied Chemistry for Engineering
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• v.9 no.2
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• pp.165-171
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• 1998

The $Y_1Ba_2Cu_3O_{7-x}$(123) superconductor powders were prepared by pyrophoric synthesis method(PSM) using $Y_2O_3$(99.9%), $BaCO_3$(99.9%), and CuO(99.9%) powders. The phase formation and reaction kinetics of 123 superconductor manufactured with powders prepared in various pHs of pyrophoric synthetic solution have been studied through the experiments at various heat treatment temperatures and times. Inductively coupled plasma(ICP) spectroscopy and scanning electron microscopy(SEM) measurements were performed to examine the composition and morphology of the sample. X-ray diffraction(XRD) analysis was done to determine phase formation and conversion ratio of Y-Ba-Cu-O systems. The 123 powder prepared at pH 7(${\pm}0.3$) yields the best result in terms of purity, homogeneity, and reactivity. The activation energies(${\Delta}E_a$) of 123 phase formation were found to be 191 kJ/mol and 230kJ/mol in solid state reaction method and pyrophoric synthesis method, respectively.

• Applied Biological Chemistry
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• v.42 no.4
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• pp.304-309
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• 1999

Two Lectins, designated FVL-1 and FVL-2, were isolated and purified from the fruiting bodies of edible mushroom Flammulina veluripes using ammonium sulfate fractionation, ethanol treatment, DEAE-TOYPEARL ion-exchange column chromatography, and TSK-Gel HW-55F column chromatography. Specific activity increased 18 folds for FVL-1 and 7.9 folds for FVL-2 from ethanol treated sample. SDS-PAGE of FVL-1 and FVL-2 gave apparent molecular mass of 10.6 kDa and 37 kDa, respectively. FVL-2 agglutinated all type of human erythrocytes (A, B, AB, and O). However, FVL-1 agglutinated more human erythrocyte type O than type A, B, and AB. The hemagglutination activities of the FVL-1 were effectively inhibited by bovine submaxillary and porcine stomach mucins(BSM and PSM), fetuin, asialofetuin and cations, such as $Cu^{2+}$, $Mg^{2+}$, $Ca^{2+}$, $Mn^{2+}$ and $Fe^{2+}$. However, FVL-2 was not inhibited by any cations. The hemagglutination activities of the two lectins were not inhibited by the sugar, such as lactose, galactose and sugar derivatives. FVL-1 and FVL-2 were stable at pH $5{\sim}11$ and pH $4{\sim}7$, respectively. FVL-1 was stable below $55^{\circ}C$ and FVL-2 was below $45^{\circ}C$.

• Korean Journal of Social Welfare
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• v.67 no.4
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• pp.279-299
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• 2015

This study examines the impact of Long-Term Care Insurance(LTCI) on family caregivers(especially focused on female household members) labor supply in South Korea. When public care and informal care are substitutes, LTCI will change allocation of time of family caregivers to spend more time to paid work. The impact of LTCI on labor supply depends on each country's institutional level of public care services. If public care can not substitute for informal care, labor supply of family caregivers will not rise significantly. The conclusions of vigorous empirical study from western countries' are incompatible and problem of endogeneity in terms of methodology has been raised consistently. The dataset of this study are used the third and ninth waves of Korea Welfare Panel. As a result, the introduction of LTCI had no effect on labor supply of household members. Robust findings suggest the positive effects of caregiving on labor market outcomes in simple comparison t-test, but not in fixed-effect regression. Compared with western countries, South Korea's public care services can be interpreted as a supplement to only part that remained at the level does not substitute informal care. These findings may suggest that if LTCI become much more prevalent in the future, senior citizens and family members will be able to choose the LTCI arrangement that best suits their needs.

• Environmental and Resource Economics Review
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• v.28 no.4
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• pp.527-556
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• 2019

In Korea, nearly 100 billion won is spent annually under the name of energy voucher on 600,000 households for the last five years, and this is a unique case and hard to monitor worldwide. Therefore, no studies have been conducted to assess impacts of the energy voucher on energy consumption and cost burden alleviation for beneficiaries. This paper aims to demonstrate the effectiveness of energy vouchers in terms of energy expense. The propensity score matching was conducted on samples of low-income households based on the Korea Welfare Panel. Then, simple Difference-In-Differences and Fixed-Effect Difference-In-Differences models were applied to estimate the effect of energy vouchers. In results, the beneficiaries of energy vouchers would spend an additional 4,371~4,870 won per month on energy consumption. The ratio is equivalent to 51.9~57.7 percent of the aid, which is also the highest when compared with 23~56 percent of U.S. Food Stamp. In terms of energy welfare, voucher payment could become one of the best management practices. However, identifying the blind spots as non-reciprocal households and expanding the differential support mechanism that reflects the energy consumption environment should be solved in the future.

• Membrane Journal
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• v.32 no.6
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• pp.367-382
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• 2022

Numerous metal-organic frameworks (MOFs) produced by periodic combinations of organic ligands and metal ions or metal-oxo clusters have led the way for the creation of energy-efficient membrane-based separations that may serve as viable replacements for traditional thermal counterparts. Although tremendous progress has been made over the past decade in the synthesis of polycrystalline MOF membranes, only a small number of MOFs have been exploited in the relevant research. Intercrystalline defects, or nonselective diffusion routes in polycrystalline membranes, are likely the reason behind the delay. Postsynthetic modifications (PSMs) are newly emerging strategies for providing polycrystalline MOF membrane diversity by leveraging advanced membranes as a platform and improving their separation capabilities via physical and/or chemical treatments; therefore, neither designing and developing MOFs nor tailoring membrane synthesis techniques for focused MOFs is necessary. In this minireview, seven subclasses of PSM techniques that have recently been adapted to polycrystalline MOF membranes are outlined, along with obstacles and future directions.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.33 no.5
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• pp.1969-1980
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• 2013

The Traffic congestion is caused by the increasing traffic demand. Thus, economic losses have been increasing every year. To solve these problems, car sharing and rental car systems that are equipped with IT technologies emerge. Car sharing has many advantages-the alleviation of the traffic congestion, the saving of maintenance cost for cars, the reduction of car possessiveness, the solution for the hassle of car ownership, for business and personal duty, and the improvement of connectivity between public transportations-. The goal of the car sharing is to achieve low-carbon and eco-friendly transportation. In this study, we review papers related to the car sharing system and the cost system of traffic systems. We estimate the optimal cost of the cloud traffic system that is one of the car sharing services. We suggest a methodology to estimate operational cost and use cost through the analysis of cost system between similar traffic means. The range of the maximum and minimum cost was determined through the comparison and analysis of similar traffic means. Expected demand and the cost that people are willing to pay were estimated through optimized value pricing. The minimum cost per hour that was compared to the cost of rental car was estimated at 5,333 won and the maximum cost per hour that was compared to taxi cost was estimated at 17,700 won. The cost for users was estimated at 6,930 won. The cost of 50% demands was estimated at 6,550won. Future studies should analyze service hours of users, weather, demand pattern and trend and consider them into the cost estimation.

• Journal of Biosystems Engineering
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• v.28 no.3
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• pp.217-224
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• 2003

To find out heating load and to determine the power of heat pump compressor for the Ondol room heating the COP of heat pump, the variation of Ondol room air temperature, the variation of ambient temperature and power consumption of heat pump are analyzed. The results from this study were summarized as follows: 1. The COP of the heat pump in close loop decreased as the ambient air temperature. The COP was 2.26 when the temperature difference of condenser was $20\pm3^{\circ}C$. 2. The Ondol surface temperature was $25\pm3^{\circ}C$ when the hot water of $40^{\circ}C$ was supplied from hot water storage tank to the Ondol and the temperature difference between the Ondol surface and the room air temperature was $7~8^{\circ}C$. 3. The ratio of thermal conduction heating load to total heating load in Ondol heating space was found to be 83% and ratio of ventilation heating load was 17%. Therefore, the thermal conduction heating load was confirmod to be a major heating load in Ondol heating space. 4. In case of the ambient temperature of $3.2^{\circ}C$, the efficiency of heat exchange of Ondol heating system was 85%. 5. The heating load per Ondol heating surface area and volume of Ondol room space were theoretically analyzed. In case of the room temperature of $20^{\circ}C$ and the ambient temperature of $-3.2~3.8^{\circ}C$, the heating load per Ondol surface area was 115.8~167.6kJ/h ㆍ㎥ and per Ondol mom space volume was 50.2~72.7kJ/h ㆍ㎥. 6. The compressor power of heat pump fur the Ondol room heating could be determined with the heating load analyzed in this study In case of the Ondol room air temperature of 17~2$0^{\circ}C$ and the ambient temperature of -5~3.8$^{\circ}C$, the compressor power of heat pump per Ondol surface area was analyzed to be $2.3\times10^{-2}psm^2$, and per volume of Ondol room space $1.0\times10^{-2}1.4\times10^{-2}ps/m^2$ps.

• Journal of Korea Technology Innovation Society
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• v.21 no.2
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• pp.767-787
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• 2018

Technology-driven innovation and job-creation has each been the subject of much scholarly attention, but have largely been considered separately rather than in conjunction with each other. While the previous literature on economics pinpointed the macro effects on industry-level, this study explores the micro-level comparisons on innovation sources over the employment and financial performances. The PSM (propensity-score matching) analysis presents that firms, involved in an inward technology, tend to have higher employees with dominant technology capabilities than in-house R&D firms. The in-house R&D firms, on the contrary, have superior financial performances, suggesting that external technology commercialized firms suffer from low transformative efficiency. The mediation test analysis corroborates that the external technology-driven innovation induces more human resources in internalizing the exogenous technology. The positive relationship between R&D innovation and employment allow verification of the government's intervention in the promotion of technology commercialization in public sector. On the other hand, it also signals that the policy needs to enhance the recipient firms' commercializing capacity rather than a 'one-hit' transaction.

• Journal of the Korean Society of Food Science and Nutrition
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• v.42 no.3
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• pp.478-486
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• 2013

The purpose of this study was to analyze consumer consumption and product concept demands of Korean rice-wine. An online survey, conducted from April 28, 2010 to May 6 2010, targeted 200 consumers in Seoul and the Gyeonggi-do area. More than half of the respondents (51.3%) drank rice-wine because of the taste. The common reasons for dissatisfaction with rice-wine were hangovers (35.7%) and taste (16.9%). From analyzing rice-wine preferences, the most preferred ingredient was rice (57.8%), while the most preferred aroma and taste was derived from the fruit (48.7% and 58.4%, respectively). The most common methods consumers observed for promoting rice-wine consumption were the "development and management of rice-wine brands" (59.7%), and "continuous promotion" (44.8%). The most important attributes of a rice-wine product included its taste (4.60), followed by its quality (4.41) using 5-point Likert scale. An importance-performance analysis (IPA) was performed for the 17 attributes of rice-wine and identified targets for product management strategies, including the "usage of domestic ingredients", "ease of purchase", clarity of "product information", and "external image". Therefore, developing solid concepts in marketing strategy are required and may be achieved by understanding the consumer preferences and demands of rice-wine.