• Journal of Distribution Research
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• v.13 no.3
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• pp.127-154
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• 2008

For the large scale retailers such as chain discount stores and specialty stores, having measurement tool to maintain service quality can be very crucial to sustain high and same level of service qualities around multiple stores. This study aims to develop service quality scales of large-scale stores using Korean discount store cases. We have studied the previous service quality measures including RSQS(Retail Service Quality Scale) and have modified and developed our own scale model called KD-SQS(Korea Discount Service Quality Scale). The following six components have been revealed as the basic dimensions of service quality of Korean discount stores: basic benefits, promotion, personal interactions, physical aspects, policy and additional convenience. Our scales have been verified through various validity and reliability tests.

• KIPS Transactions on Computer and Communication Systems
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• v.5 no.8
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• pp.197-210
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• 2016

Lately smartphone uasage is increasing and many Internet of Things (IoT) devices support wireless communications. Accordingly, small base stations which called femtocells are supplied to prevent saturation of existing base stations. However, unlike the original purpose of the femtocell with the advanced hacking technologies, Vulnerability such as gaining the administrator authority was discovered and this can cause serious problems such as the leakage of personal information of femtocell user. Therefore, identify security threats that may occur in the femtocell and it is necessary to ways for systematic vulnerability analysis. In this paper, We analyzed the security threats that can be generated in the femtocell and constructed a checklist for vulnerability analysis using the Threat Modeling method. Then, using the constructed checklist provides a scheme that can improve the safety of the femto cell through the actual analysis and taken the results of the femtocell vulnerabilities analysis.

• Journal of rehabilitation welfare engineering & assistive technology
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• v.7 no.1
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• pp.39-43
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• 2013

In this paper, we present a effective method of gait rehabilitation training using critical point of median frequency in muscle fatigue analysis using EMG. To target the five healthy volunteers, EMG signal were measured in the quadriceps femoris muscle and the tibialis anterior muscle in order to determine muscle fatigue. We performed a test targeting three adult male for 30 minutes on a treadmill at a speed of 6km/h same. EMG signal analysis in frequency and median frequency is calculated to quantification of muscle fatigue, and calculated the critical point which is saturated by muscle fatigue during 30 minutes. We set saturated point the threshold which muscle can withstand. The results of this paper, we are able to quantify the threshold of the muscle.

• Korean Journal of Soil Science and Fertilizer
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• v.36 no.4
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• pp.193-199
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• 2003

Electrical conductivity (EC) is a major indicator of soil salinity. Measurement of EC in saturation-paste extract of soil (ECe) is a standard way to evaluate soil salinity. However, many of the data on soil salinity have been obtained by measuring the EC of 1:5 soil-water extract (EC1:5) or salt percentage which is calculated from EC1:5 by multiplying a conversion factor. We analyzed 90 soil samples collected from 9 reclaimed tidelands in Korea, and derived relationships between ECe and dilution factors (DF1:5) which can convert EC1:5 to ECe in 2 soil textural groups at 5 salinity levels. Regression equations between ECe and DF1:5 were DF1:5 = 1.3624In(ECe) + 5.1386($r^2=0.37^{***}$) for soils of more than 50% silt content, DF1:5 = 1.9505In(ECe) + 5.3679($r^2=0.66^{***}$) for soils of less than 50% silt content. And the relationship for all soils investigated was DF1:5 = 1.4001In(ECe) + 5.4865($r^2=0.51^{***}$). From the relationships, conversion factors for calculation of ECe from EC1:5 of salt percentage data were estimated for soils of different textures and salinity levels.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.4
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• pp.39-48
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• 2020

Since the fire accident of ESS (energy storage system) occurred at Gochang KEPCO Power Testing Center in August 2017, 29 fire cases with significant property losses have occurred in Korea. Although the cause of fire accidents have not been identified precisely, it should be considered battery and PCS (power conditioning system) as well as unbalance issues in the distribution system. In particular, circulating currents in a neutral line of a grid-connected transformer, which can affect a magnetized current, may have a negative effect on the ESS with unintentional core saturation and surge voltages at the secondary side of the transformer. Therefore, this paper proposes the modeling of the distribution system, which was composed of a substation, grid-connected transformer, and customer loads using PSCAD/EMTDC S/W, to analyze the phenomena of circulating current and surge voltages of the transformer with unbalanced currents in the distribution system. This paper presents a countermeasure for a circulating current with the installation of NGR (neutral grounding resistor) in grid-connected transformer. From the simulation results, it is clear that exceeding the circulating current and surge voltage at the secondary side of the transformer can be one of the causes of fire accidents.

• Korean Chemical Engineering Research
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• v.48 no.2
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• pp.224-231
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• 2010

In GvdW EOS, a recently presented paper, shows that the characteristic status for spherical non-linear particle, of which the mutual behavior is known to be vdWf(van der Waals force) only, could be described well enough in the critical region. However, in current papers, analysis has not been done on GvdW about whether it is accurate or not, even for the particles in the linear form or those with the additional mutual behavior such as static-electricity, so there's some argument about the wide use of that. Therefore, in this paper, for the simulation in the critical region of Normal-alkane group(R=methane, ethane, propane, butane) which are the particles that has a linear charateristic and Normal-amine group($RNH_2$, R=methyl-, ethyl-, propyl-amine) where static-electricity is extremely shown, GvdW parameter values about these particles are defined, and based on this simulation, we compared results to the current EOS presented recently, and analyzed them. Through the simulation, it was shown that in case of Normal-alkane group and Normal-amine group molecules, GvdW presents an accurate critical region characteristic which is far more close to the measurement compared to current EOSs. Especially for butane with big amount in molecules, we found out that only GvdW EOS can reach close enough to the critical point.

• Korean Journal of Soil Science and Fertilizer
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• v.26 no.1
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• pp.37-42
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• 1993

Influences of metal concentration, pH and temperature on metal-ligand precipitate formation were investigated, as a part of projects for removing heavy metals from aqueous solution employing the principles in metal-ligand complexation. Aqueous solutions of HA or FA were reacted with those of heavy metals with 1:1 ratio. Efficiency of humic (HA) or fulvic acid (FA) on removing metals was evaluated by separating the precipitates from soltuions with the filtering method. When HA was a counter ligand, there existed three ranges of metal concentrations affecting precipitation : precipitate fromation was not available, was reached to the maximum, and afterwards was decreased again. The concentration ratios of metal to HA for initiating complexation were dependent upon kinds of metal and concentrations of ligand. Amount of Pb to form maximum precipitates per unit mg of HA was 1.3 times higher than that of Cu. When FA was a counter ligand, concentrations of metal-FA precipitates were increased proportionally with the treated metal concentrations. Efficiency of FA fro removing Pb was nearly 100%, but it was ranged from 12 to 19% for Cu, depending on FA concentration. pH exerted a considerable effect on complexation between Pb and FA, showing precipitates were increased six times at most per unit increase of pH. Ranges of pH increasing significantly the mounts of precipitates were coincied with pH jump ranges of the titration curve of organic ligands. As increasing temperature from 15 to $55^{\circ}C$, increases of FA-Cu precipitates were doubled, but those of FA-Pb were accounted for only 6%, However, HA-metal complexation was not affected by temperature.

• Restorative Dentistry and Endodontics
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• v.32 no.6
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• pp.498-513
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• 2007

Since it was reported that incipient enamel caries can be recovered, previous studies have quantitatively evaluated that enamel artificial caries have been, remineralized with fluoride showing simultaneously the increase of width of surface layer and the decrease of width of the body of legion. There is, however, little report which showed that remineralization could occur without fluoride. In addition, the observations on the change of hydroxyapatite crystals also have been scarcely seen. In this study, enamel caries in intact premolars or molars was induced by using lactic acidulated buffering solutions over 2 days. Then decalcified specimens were remineralized by seven groups of solutions using different degree of saturation(0.212, 0.239, 0.301, 0.355) and different pH(5.0, 5.5, 6.0) over 10 days. A qualitative comparison to changes of hydroxyapatite crystals after fracturing teeth was made under SEM(scanning electron microscopy) and AFM(atomic force microscopy). The results were as follows: 1. The size of hydroxyapatite crystals in demineralized area was smaller than the normal ones. While the space among crystals was expanded, it was observed that crystals are arranged irregularly. 2. In remineralized enamel area, the enlarged crystals with various shape were observed when the crystals were fused and new small crystals in intercrystalline spaces were deposited. 3. Group 3 and 4 with higher degree of saturation at same pH showed the formation of large clusters by aggregation of small crystals from the surface layer to the lesion body than group 1 and 2 with relatively low degree of saturation at same pH did. Especially group 4 showed complete remineralization to the body of lesions. Group 5 and 6 with lower pH at similar degree of saturation showed remineralization to the body of lesions while group 7 didn't show it. Unlike in Group 3 and 4, Group 5 and 6 showed that each particle was densely distributed with clear appearance rather than crystals form clusters together.

• The Journal of Industrial Distribution & Business
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• v.2 no.2
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• pp.39-45
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• 2011

The Korean distribution industry is gearing up for an endless competition. Greeting low growth era, less competitive parties will be challanged seriously for their survival. But for large discount stores, they have shown steady annual growth for years. However, because of the saturation for numbers of stores, the difficulty of gaining new sites, and the changes in the consumer's consumption behavior caused by the recession, now they are seeking for a new customers-based business formats. Accordingly, a large corporate comopanies made supermarkets which are belonged to affiliated companies of large corporate comopanies. They based on the strong buying power, focused on SSM(Super Super Market) ave been aggressively develop nationwide multi-stores. The point is that these stores are threatening at small and medium-sized, community-based private supermarkets. Private supermarkets and retailers, who are using existing old operation systems and their dilapidated facilities, are losing a competitive edge in business. Recent the social effects of large series of corporate supermarkets for traditional markets has been very controversial, and commercial media, academia, and industry associated with it have been held many seminars and public hearings. This may slow down the speed in accordance with the regulations, but will not be the crucial alternative. The reason for this recent surge of enterprise-class SSM up, one of the reasons is a stagnation in their offline discount mart, so they are finding new growth areas. Already in the form of large supermarkets across the country got most of the geographical centre point and is saturated with stages. Targeting small businesses that do not cover discount Mart, in order to expand business in the form of SSM is urgent. By contrast, private supermarkets are going to lose their competitiveness. The vulnerability of individual supermarkets, one of the vulnerabilities is price which economies of scale can not be realized so they are purchasing a small amount of products and difficult to get a quantity discount. The lack of organization and collaboration, and education which is not practical, caused the absencer of service-oriented situations. As a first solution, making specialty shops which are handling agricultures, fruits and vegetables and manufactured goods is recommended. Second, private supermarkets franchisees join the organization for the organization and collaboration is recomaned. It can be meet the scale of economy and can be formed a alternative business formats to a government. Third, the education is needed as a good service will get consumer's awareness. In addition, a psychological stores operating is also one way to stimulate consumer sentiment as SSM can't operate. Japan already has a better conditions of their lives through small chain expression. This study includes the vulnerabilities of private supermarkets, and suggests a competitiveness reinforcement strategies.

• Journal of the Korean Society of Food Science and Nutrition
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• v.43 no.2
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• pp.309-317
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• 2014

The purpose of this study was to investigate convenience foods at convenience stores, by examining consumption patterns, as well as the degree of checking food-nutrition labeling. In this study, 208 workers in Busan in their 20s or 30s were surveyed using 1:1 interview questionnaires. The weekly usage frequencies of cup-ramyeon, gimbap, ramyeon, and sandwiches were 41.0%, 39.4%, 32.7%, and 19.0% respectively. The usage frequency of convenience foods was 12.0% for 'over 5 times/week', 23.0% for '3~4 times/week', 31.7% for '1~2 times/week', 29.8% for '1~2 times/month', and 3.4% for zero usage. Workers in their 20s showed a significantly (P<0.05) higher rate in the '3~4 times/week' as well as '1~2 times/week' intervals than workers in their 30s. Single people showed a significantly (P<0.01) higher rate than married people. Workers in their 20s showed a significantly higher score for the '3~4 times/week' as well as '1~2 times/week' intervals (P<0.05). The mean score of checking food labeling was 4.02/5.00 for the manufacturer's date, or expiration date, 3.23/5.00 for weight or volume, 2.99/5.00 for cooking method, and 2.85/5.00 for storage method. Females showed significantly (P<0.01) higher rates for checking the manufacturer's date or expiration date, as well as source of the raw material. Single workers showed significantly (P<0.01) higher rates for checking the manufacture's or expiration date as well as storage method. The mean score for checking nutrition labeling was 3.06/5.00 for calories, 2.84/5.00 for trans fat, 2.80/5.00 for sodium, and 2.76/5.00 for cholesterol. Females showed a significantly (P<0.01) higher rate for six of 10 items. Workers in their 20s showed a significantly (P<0.05) higher rate for four of 10 items. Expert officials showed significantly higher rate for six of 10 items (P<0.05) and two of 10 items (P<0.01), respectively.