• Korean Journal of Food Science and Technology
• /
• v.41 no.2
• /
• pp.210-214
• /
• 2009

This study identified microbial risk factors in agricultural products processing center (APC) through the microbial hazard analysis to introduce good agricultural practices (GAP) system in APCs. Samples were collected from surroundings (basket, tray loader, weighing cup, collector, box) and workers by swabbing (glove and cloth) and glove juice method (hand) to enumerate total bacteria, coliform, Staphylococcus aureus, Escherichia coli, Escherichia coli O157:H7 and Salmonella. The levels of total bacterial and coliform populations recovered from surroundings were 2.4-5.7 log CFU/100 $cm^2$ and 2.3-5.7 log CFU/100 $cm^2$ or hand for surroundings, and workers, respectively samples were 2.3-5.7 log CFU/100 $cm^2$ or hand. Escherichia coli populations were determined to be below detection limit. S. aureus and Salmonella populations recovered from surroundings were 3.0-4.4 log CFU/100 $cm^2$ and close to detection limit, respectively. Corresponding bacterial populations to worker's samples were 2.8-5.2 log CFU/100 $cm^2$ or hand (S. aureus) and below detection limit (Salmonella). Bacterial populations of APC certified facilities were similar (p${\geq}$0.05) with those of uncertified facilities. These results showed that this study should be useful in development of GAP models to improve microbial safety in APCs.

• Journal of the Institute of Electronics Engineers of Korea TC
• /
• v.39 no.1
• /
• pp.20-33
• /
• 2002

Usage of ATM AAL2 packets becomes dominant to increase transmission efficiency of voice traffic in the backbone network. In case of voice service that uses AAL2 mechanism, if resources of network are enough, connection of new call is accepted. However, due to packets generated by the new call, transmission delay of packets from old calls can increase sharply. To control this behavior, in this paper we present an AAL2 buffer management scheme that allocates a virtual buffer to each call and after calculating its propagation delay variation(PDV), decides to drop packets coming from each call according to the PDV value. We show that this packet dropping algorithm can effectively prevent abrupt QoS degradation of old calls. To do this, we analyze AAL2 packet composition process to find a critical factor in the process that influences the end-to-end delay behavior and model the process by K-policy M/D/1 queueing system and MIN(K, Tc)-policy M/D/1 queueing system. From the mathematical model, we derive the probability generating function of AAL2 packets in the buffer and mean waiting time of packets in the AAL2 buffer. Analytical results show that the AAL2 packet dropping algorithm can provide stable AAL2 packetization delay and ATM cell generation time even if the number of voice sources increases dramatically. Finally we compare the analytical result to simulation data obtained by using the COMNET Ⅲ package.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2008.04a
• /
• pp.313-316
• /
• 2008

Corrosion of steel in the reinforced concrete structures is one of the main reason of degradation. It causes that lifetime of structures is shortened and maintenance cost is increased. And it also causes degradation of structures like bridges which are under repeated load. So, many research have been performed about FRP rebar. But there are few research about FRP rebar under fatigue. This study is to examine flexural characteristic of concrete beam reinforced with FRP(CFRP, GFRP) rebar under static and fatigue for considering the application. The specimens that used in this study are designed by ACI 440.1R-06 and reinforced with CFRP(CR) or GFRP(GR) overly. In the result of static bending test, all specimens were failed at compression phase. In fatigue test, the fatigue stress level was 60%, 70% or 80% of the static bending strength. Most of the specimens seemed to be compressive failure, but CR-60 and CR-70 specimens were failed with rupturing of tension bar.

• Korean Journal of Social Welfare
• /
• v.52
• /
• pp.5-32
• /
• 2003

This paper examines the labor entry of conditional welfare recipients. This paper focuses on two questions. First, what is the percentage of conditional welfare recipients who have labor entry? Second, what are the predictors in the labor entry and the duration to the entry? Using Data about 917 welfare recipients who participated in the self-sufficiency programs of the Offices for Secure Employment in Seoul, this paper attempts to answer the above questions. Logistic regression analysis and survival analysis are adopted to identify variables predicting labor entry of conditional welfare recipients. This paper also utilizes a multiple imputation method to deal with the limitation of data by the missing values in some variables. The major findings are as follows: about 43.8% of the conditional welfare recipients have successful labor entry; and in the labor entry and the duration to the entry, gender, household, information and referral services for employment, health and willingness for self-sufficiency are the predictors that are statistically significant. Among these variables, health and willingness for self-sufficiency are more noticeable; it is recognized that programs to care for health of welfare recipients who want to have the labor entry and counseling programs to strengthen welfare recipients' willingness for labor entry are very important for them to be successful in the labor entry. This paper provides a basic knowledge about realities of the conditional welfare recipients' labor entry, identifies research areas for further research, and develops policy implications for their self-sufficiency.

• Journal of Korea Port Economic Association
• /
• v.27 no.2
• /
• pp.297-311
• /
• 2011

This paper deals with a strategic investment decision model for improving investment profit in shipping industry. Despite the quantitative expansion of Korean shipping business, many shipping firms have suffered financial difficulties due to financial and operating risks that result from the characteristics of capital-intensive business as well as of volatility of shipping markets. As a result, managers in charge of making an investment decision, particularly in tramper business sector, are required to take both financial and operating risk factors into consideration. Put it differently, managers are strongly recommended to avoid these risks by ship asset play; buy-low and sell-high, which results in considerable capital gain and cost reduction. In addition, managers in shipping industry are also recommended to consider the ship chartering investment alternative when the freight markets show extreme volatility as the case of 2008 triggered by sub-prime mortgage financial crisis in USA. For example, the BDI suffered plunging down from 1000 in 2008 to 100 in 2010. Consequently, the 4th largest shipping company in Korea, DAEHAN Shipping Co., has collapsed primarily due to excessive tonnage expansion during the peak time of bulk market. In sum, the strategic investment decision model, suggested in this paper, is designed to include such factors as capital gain by asset play, timely chartering for alternative shipping service, and optimization of operating profit by tonnage adjustment in accordance with change in the shipping markets concerned.

• Journal of Korea Port Economic Association
• /
• v.32 no.2
• /
• pp.123-135
• /
• 2016

This study uses Data Envelopment Analysis(DEA) to investigate the management efficiency of Korean shipping companies based on business administration costs such as corporate entertainment, advertisement, and labor costs. We analyze shipping enterprises listed on the Korean stock market of the period of 2010-2014. Corporate entertainment, advertisement and labor costs are used as input variables and sales and net income are used as output variables. We use technical efficiency, pure technical efficiency, scale efficiency and returns to scale to propose a plan to improve the efficiency of inefficiency decision-making units (DMUs). The results of the efficiency analysis show that six of the DMUs in the technical efficiency of CCR model and eight of the DMUs in the pure technical efficiency of BCC model are in efficient state. In terms of return to scale, six of the DMUs(24% of all DMUs) show increasing returns to scale, while 13 DMUs(52% of all DMUs) showdecreasing returns to scale. Because multiple efficient state for DMUs exist in the technical efficiency analysis, we conduct a super efficiency analysis. The results show that the efficient state of the twomost efficient DMUs are 1.314 and 1.243, respectively. This implies that these DMUs could maintain their current levels of the efficiency if they increase the amount spent on advertisements, corporate entertainment and labor costs by 31.4% and 24.3%. respectively. We conclude this study by providing the efficiency states of each DMU and target for improving the inefficiencies in each case.

• Journal of the Korean Society for Railway
• /
• v.19 no.2
• /
• pp.262-269
• /
• 2016

Subway station scales are determined by peak predictions. In this study, the purpose behind the installation of a subway is public transportation convenience and public interest, but economic validity is also important. By proving that the scale of the station is excessive with regard to the target station size for Seoul subway Line 5-8, a reasonable plan. can be sought. According to station installation standards, the area of the station under investigation here is out of the service levels by six stages (A~F), and it must be four or more levels (D). The Actual level for the B level is a two-step design. The Actual ratio for over- Peak predictions is only 17.8% on average. The results of measurements of the excess area and determination of the excessive costs were analyzed by subdividing the area and by calculating it based on the B level, finding that it is possible to provide benefits for customers only in the current design, with an area ratio of 16.3%. Given the weight, it was estimated that current conditions can meet the needs of only 18.6% of the current area. Simplifying the scale calculation method of the station, it is convenient, safe, and advantageous to move citizens only if the scale can be streamlined. Then, with a reduced initial investment, maintenance costs during the operation can be reduced.

• Journal of Applied Tourism Food and Beverage Management and Research
• /
• v.16 no.1
• /
• pp.43-69
• /
• 2005

Generally, brand is the title for discriminating their own goods and service from other competitive company, brand-image means customer's good and bad affection or loyalty the brand of specific company. Customers often choose the goods according to the value of goods brand. In terms of this viewpoint, the value of company's brand is very important factor to the company's success. Brand-image also effects customers on selling company's goods. Specially, to the hotel business that should ensure lots of customer for a long period with the interest and credit of customers, its brand-image is more significant. What the image is looked upon as a important factor in marketing is due to the difficulty of discrimination against goods standardized in price and quality. Therefore, the company's image acts as a more important marketing factor in the high industrial society. Also it means a lot to the customer's purchasing behavior. When the company's brand-image is recognized or discriminated, customer's memory is longer and customer's reliability is raised than other company's advertisement and public information. Nowadays, most of hotels are perceiving the importance on their own brand-image but in the lack of deep study and systematic strategy in reality. The purpose of this study is to research the effect on customer's purchasing intention of hotel brand-image and choice-attribution. The empirical research has been done from 23April, 2004 to 20May, 2004. Data were collected from general customers who are using hotel located in Taegu. In conclusion, hotel brand-image depends highly on, the service quality of hotel staff and reputation of hotel. Besides, this acts on customer's hotel choice decisively.

• Journal of Bio-Environment Control
• /
• v.19 no.3
• /
• pp.123-129
• /
• 2010

A study on modeling of medium temperature drops of the elevated-bench hydroponic system for strawberry cultivation during low temperature season was conducted. Four different conditions were used for the experiment. These consisted of two kinds of bed types (plant, V), four kinds of medium (rice, perlite, rice hulls80% and peatmoss20%, perlite80% and peatmoss20%), two kinds of mulched bed (mulched, non mulched) and four kinds of greenhouse air temperature (l.5, 3.2, 5.0, $6.7^{\circ}C$), and the results were summarized as follows: Temperature drop of medium in the V-bed was slower than that in the plant bed, showing better insulation effect of V-bed. Temperature drop of medium with mulching on the top of the bed was slower than the case without mulching, as a result, the beneficial effect of temperature drop was appeared in mulched bed. Linear regression of the temperature descent rate and the temperature difference between medium and air showed significant correlation. The regression equation for the Pearlite80% and Peatmoss20% in the V-bed was f(x) = -0.2656 + 0.1345x at the $R^2$ of 0.9269. Using the model, the temperature drop during night can be predicted for the various media at the different depths.

• Tunnel and Underground Space
• /
• v.8 no.4
• /
• pp.307-320
• /
• 1998

Tunnel lining is the final support of a tunnel and reflects the results of the interaction between ground and support system. Recently it is very difficult to support and manage the tunnel because the cracks on tunnel lining cause many problems in supporting and managing tunnels. Therefore the analysis of the cracks is quite strongly required. In this study, mechanical behaviour of a tunnel lining was examined by model tests and by numerical analyses. Especially the model test was examined for double linings including shotcrete and concrete lining. The model tests were carried out under various conditions taking different loading shapes, horizontal stresses, thicknesses of linings and double lining, vault opening behind the concrete lining and rock-like medium surrounding the lining. Due to horizontal stress, compressive stress prevailed on the lining. Thus the bearing capacity of the lining increased. The existence of a vault opening behind the concrete lining reduced the bearing capacity by the similar amount of reduction of concrete lining thickness. Rock-like medium cast around the side wall of the lining restrained the deflection of the lining, and the bearing capacity for cracking and failure increased vary much. In numerical analyses a algorithm which can analysis the double lining by introduction of interface element was developed. And the results of the numerical analyses were compared with the results of the model tests.