• Korean Journal of Food Science and Technology
• /
• v.31 no.2
• /
• pp.285-292
• /
• 1999

An analytical method applicable to quality control and its optimum conditions were studied for rapid and efficient analysis of sorbic and benzoic acids used as preservatives in the commercial soybean paste. In gas chromatographic analysis of sorbic and benzoic acids, the application of HP-FFAP (acid modified polyethylene) wide bore column improved the separation ability significantly. By setting the oven temperature of GC to $200^{\circ}C$, the total elapsed time for quantitative analysis was also reduced to the level required in using packed column. By extracting sorbic and benzoic acids from soybean paste with an automatic steam distillation device, the elapsed time for analysis was reduced by 80% more compared to using conventional steam distillation method. The recoveries of sorbic and benzoic acids by the automatic steam distillation were 98.1% and 99.9%, respectively. The sorbic acid was found in 3 samples of 14 commercial soybean pastes, of which contents were $466{\sim}530ppm$, while $0.3{\sim}4.4ppm$ of benzoic acid was found in all the samples.

• Journal of Korean Society of Industrial and Systems Engineering
• /
• v.40 no.4
• /
• pp.191-202
• /
• 2017

The purpose of this study is to develop an engineer competency model using Analytical Hierarchy Process (AHP) to improve the national technical qualification system. Korea has managed technical human resources at the government level through the operation of a national technical qualification system that certifies engineers with national certificates or technical grades by laws. However, there have been increasing concerns that the government system is separated from global standards and does not reflect an engineer's comprehensive capabilities. For these reasons, the new architecture of the system has been continuously discussed and becomes a major policy issue of the Korean government. For the development of the engineer competency model, domestic and global models were separately structured using 554 valid questionnaires with a consistency ratio (CR) of 0.1 or less. The relative importance of engineer competency factors in a domestic model was career (0.383), qualification (0.253), academic degree (0.195), and job training (0.169) whereas the order in the global model was career (0.308), global ability (0.237), job training (0.175), domestic qualification (0.147), and academic degree (0.134). The results of AHP analysis indicated that the evaluation factors and methods recognized by engineers were different from a current government model focusing on domestic qualifications. There was also perceptual difference in the importance of engineer evaluation factors between groups depending on the type of organizations and markets. This means that it is necessary to reflect the characteristics of organizations and markets when evaluating engineer competency. Based on AHP analysis and literature reviews, this paper discussed how to develop a new engineer competency index (ECI) and presented two effective index models verified by simulation test using 59,721 engineers' information. Lastly, the paper discussed major findings of our empirical research and proposed policy alternatives for the improvement of a national engineer qualification system. The paper contributes to the management of technical human resources since it provides quantitative competency models that are objectively developed by reflecting market recognition and can be effectively used by the policy makers or firms.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.39 no.11
• /
• pp.1169-1174
• /
• 2015

Risk-Risk-based inspection (RBI) has been developed in order to identify risky equipments that can cause major accidents or damages in large-scale plants. This assessment evaluates the equipment's risk, categorizes their priorities based on risk level, and then determines the urgency of their maintenance or allocates maintenance resources. An earlier version of the risk-based assessment software is already installed within the equipment management system; however, the assessment is based on examination by an inspector, and the results can be influenced by his subjective judgment, rather than assessment being based on failure probability. Moreover, the system is housed within a server, which limits the inspector's work space and time, and such a system can be used only on site. In this paper, the development of independent risk-based assessment software is introduced; this software calculates the failure probability by an analytical method, and analyzes the field inspection results, as well as inspection effectiveness. It can also operate on site, since it can be installed on an independent platform, and has the ability to generate an I/O function for the field inspection results regarding the period for an optimum maintenance cycle. This program will provide useful information not only to the field users who are participating in maintenance, but also to the engineers who need to decide whether to extend the lifecycle of the power machinery or replace only specific components.

• International Commerce and Information Review
• /
• v.14 no.2
• /
• pp.147-172
• /
• 2012

The aim of this research is to identify the competencies required by freight forwarding company logistics managers or supply chain managers. And this research also attempts to show their relative importance and key knowledge areas that require improvement. Using a survey questionnaire, data was collected against forty three logistics and supply chain management skills or competencies, which were then grouped into four categories and analysed. The Analysis revealed that supply chain awareness, ability to make decisions, analytical skill, communication skill, supply chain cost, people skill, and integration of internal or external information flow which belong to logistics planning group are considered the most important competencies for effective and efficient logistics functioning. On the other hand, reverse logistics and IATA regulations from environmental awareness group show little influence on logistics managers for improving their logistics performances. The results have implications for a variety of parties including prospective logisticians, students, teachers and companies considering expanding their business to Chinese market. For example, the results permit companies to employ appropriate logistics managers who are qualified with sufficient skills and competencies suggested in this research. In the case of practitioners, the results provide a benchmark for comparison with their current level of abilities and suggested competencies.

• International Commerce and Information Review
• /
• v.13 no.4
• /
• pp.251-274
• /
• 2011

The aim of this research is to identify the competencies required by logistics managers or supply chain managers in China. And this research also attempts to show their relative importance and key knowledge areas that require improvement. Using a survey questionnaire, data was collected against forty three logistics and supply chain management skills or competencies, which were then grouped into four categories and analysed. The Analysis revealed that supply chain awareness, ability to make decisions, analytical skill, communication skill, supply chain cost, people skill, and integration of internal or external information flow which belong to logistics planning group are considered the most important Competencies for effective and efficient logistics functioning. On the other hand, reverse logistics and IATA regulations from environmental awareness group show little influence on logistics managers for improving their logistics performances. The results have implications for a variety of parties including prospective logisticians, students, teachers and companies considering expanding their business to Chinese market. For example, the results permit companies to employ appropriate logistics managers who are qualified with sufficient skills and competencies suggested in this research. In the case of practitioners, the results provide a benchmark for comparison with their current level of abilities and suggested competencies.

• Journal of Digital Convergence
• /
• v.18 no.4
• /
• pp.23-35
• /
• 2020

This study is based on prior research cases on workplace learning, which had a significant impact on corporate research. To improve problem solving and supplementing ability by keeping the opportunity to participate in workplace learning for the weak small business owners and to strengthen opportunities for practical growth, and to propose education, policy and institutional windowing. Therefore, to establish the relationship between small business owners' workplace learning, job satisfaction, and service quality, a research hypothesis was set in the background of prior research and empirical analysis was conducted. The results from 203 questionnaires were analyzed with SPSS 18.0 program. As an analytical result, first, workplace learning had a partial positive (+) impact on job satisfaction. Second, workplace learning had a partial positive (+) impact on service quality. Third, in the relationship between workplace learning and service quality, job satisfaction played a full mediating role. From this, it was found that formal learning, the subfactor of workplace learning did not have an impact on job satisfaction and service quality, as subtitle of educational environment including offsite training and self education, systematization, and structuralization depending on the poor environment of small enterprises. Therefore, it was found that small enterprises' poor environment was revealed from the managerial, economic and social perspectives and to compensate such defect, educational, policy, and institutional strategies to strengthen the opportunity for growth and development of small enterprises can be suggested to the governmental agencies or local governments. Despite the significant results of this study, there may be limitations. Therefore, further studies should be conducted in various fields with various samples in the future, and further studies should be conducted in academic and practical relationships that can improve the service quality and management performance.

• Journal of The Korean Association For Science Education
• /
• v.37 no.5
• /
• pp.879-889
• /
• 2017

The purpose of this study is to develop the evaluation criteria for students' research reports on online science inquiry problems that promote thinking abilities. The steps of developing the evaluation criteria are as follows; First, based on previous study results and literature review, the evaluation categories of the science inquiry contents were determined: 1) knowledge, 2) logical and analytical thinking, 3) critical thinking, 4) science process skills, 5) problem-solving, and 6) creative thinking. Second, evaluation criteria are developed according to the following steps: 1) define each category, 2) identify sub-category, 3) develop evaluation criteria for all categories that could serve as guidelines in the development of scoring rubrics, and 4) expert validation processes were performed. Finally, the usability test for these evaluation categories and criteria were done by being applied to the development of real scoring rubrics for 24 problems included in e-learning contents. Then the users' feedbacks were filed and the implications of this study were discussed.

• Journal of the Korean Chemical Society
• /
• v.10 no.4
• /
• pp.166-174
• /
• 1966

The multistep mechanism of photosensitized curing reaction cinnamoylated photosensitive polymer is proposed from the energy level diagram of cinnamic acid and sensitizer, and from the fact that excess of sensitizer brings the sensitivity to a limiting value etc. Various factors which have effects on the ability of sensitizer are also discussed. The mechanism involves following steps: activation to the first excited singlet states of cinnamoyl group(C) and sensitizer(S) by their absorption of photon, their intersystem crossing to the lowest triplet state, bimolecular internal quenching by formation of excimer of sensitizer, triplet excitation energy transfer and intermolecular addition between cinnamoyl group in ground state and that in triplet state. The rate equation derived from this mechanism is $-\frac{d[C]}{dt} = \frac{K_1[C]}{K_2 + [C]}[\frac{I^c_{abs}}{K_3 + [S]} + \frac{K_4[C]}{(K_5 + [C])(K_6 + [S])}(I^s_{abs} + \frac{K_7I^c_{abs}[S]}{K_8 + [S]})]$ where $I^c_{abs}\;and\;I^s_{abs}$: the rates of absorption of photon by cinnamoyl group and sensitizer $K_n$: Constants. It is proved with the cinnamate of poly(glyceryl phthalate)(PGC) in the absence of sensitizer using the infrared analytical method and successfully applied for the experimental data reported on the effects of the degree of cinnamoyl esterification and the concentration of sensitizer upon the sensitivity.

• Korean Chemical Engineering Research
• /
• v.45 no.3
• /
• pp.249-257
• /
• 2007

The periodic square wave (PSW) model was successfully applied to the optimal design of a batch-storage network. The network structure can cover any type of batch production, distribution and inventory system, including recycle streams. Here we extend the coverage of the PSW model to multitasking semi-continuous processes as well as pure continuous and batch processes. In previous solutions obtained using the PSW model, the feedstock composition and product yield were treated as known constants. This constraint is relaxed in the present work, which treats the feedstock composition and product yield as free variables to be optimized. This modification makes it possible to deal with the pooling problem commonly encountered in oil refinery processes. Despite the greater complexity that arises when the feedstock composition and product yield are free variables, the PSW model still gives analytic lot sizing equations. The ability of the proposed method to determine the optimal plant design is demonstrated through the example of a high density polyethylene (HDPE) plant. Based on the analytical optimality results, we propose a practical process optimality measure that can be used for any kind of process. This measure facilitates direct comparison of the performance of multiple processes, and hence is a useful tool for diagnosing the status of process systems. The result that the cost of a process is proportional to the square root of average flow rate is similar to the well-known six-tenths factor rule in plant design.

• Journal of Korean Society of Environmental Engineers
• /
• v.36 no.6
• /
• pp.387-395
• /
• 2014

A highly sensitive analytical method based on stir bar sorptive extraction (SBSE) technique and gas chromatography/tandem mass spectrometry (GC-MS/MS) has been developed, allowing the simultaneous multi-analyte determination of 11 synthetic fragrances (SFs) in water samples. The stir bar coated with polydimethylsiloxane (PDMS) was added to 40 mL of water sample at pH 3 and stirred at 1,100 rpm for 120 min. Other SBSE parameters (salt effect and presence of organic solvent) were optimised. The method shows good linearity (coefficients > 0.990) and reproducibility (RSD < 10.9%). The extraction efficiencies were above 83% for all the compounds. The limits of detections (LOD) and limits of quantification (LOQ) were 2.1~4.1 ng/L and 6.6~12.9 ng/L, respectively. The developed method offers the ability to detect 11 SFs at ultra-low concentration levels with only 40 mL of sample volume. Matrix effects in tap water, river water, wastewater treatment plant (WWTP) final effluent water and seawater were investigated and it was shown that the method is suitable for the analysis of trace level of 11 SFs. The method developed in the present study has the advantage of being rapid, simple, high-sensitive and both user and environmentally friendly.