• Journal of the Korean earth science society
• /
• v.38 no.2
• /
• pp.150-160
• /
• 2017

In order to determine the porosity of rock, the 'standard test method for porosity and density of rock' proposed by the Korean Society for Rock Mechanics is commonly used. However, the standard test method, which uses a drying oven, takes 8 to 24 hours to complete the test in taking samples out of the oven every four hours and measuring the weight of the specimen. To complement these disadvantages, we devised a method for measuring rock porosity by using a microwave oven. The devised method reduced the cause of errors and the inconvenience occurred in the process of weighing samples by constructing a weight monitoring system, which monitors the drying process. A suitable heating/pause time was set up to maintain the temperature of sample below $105{\pm}3^{\circ}C$ in drying process, and an alarm system was implemented in order to stop drying process when the weight change of the rock sample is within 0.1% of the initial weight. The porosity was determined from the dry weight of the sample, which was obtained by the curve fitting of weight monitoring data. Then, the porosities obtained by using the microwave oven were compared with those obtained by the standard test method. Test results using sandstone samples showed that the porosities obtained by a microwave oven was similar to those obtained by the standard method and the porosity difference between two methods was as large as 0.4%. In addition, repeated porosity measurement using the same specimen showed that the standard deviation of the porosity, which reflects the precision of the measurement was as good as 0.23%. Therefore, a microwave oven porosity measurement system can give the porosity of rock samples with high reliability.

• Culinary science and hospitality research
• /
• v.18 no.5
• /
• pp.16-32
• /
• 2012

The purposes of this study were to understand how franchisor's influence strategies influenced franchisee's boundary spanning behaviors and how franchisor's entrepreneurship influenced franchisee's boundary spanning behaviors. This study also analyzed whether franchisor's entrepreneurship played a moderating role in the causal relationship between franchisor's influence strategies and franchisee's boundary spanning behaviors. Based on a total of 698 self-administered questionnaires obtained from franchisees(food-service unit owners or managers) in Korea, frequency analysis, exploratory factor analysis, reliability analysis and hierarchical regression analysis were conducted. The research findings showed results that firstly, promise (${\beta}$=0.292), threat (${\beta}$=-0.256), recommendation (${\beta}$=0.200), information exchange (${\beta}$=0.359), request(${\beta}$=-0.097) and legalistic plea(${\beta}$=-0.137) had a significant effect on franchisee's boundary spanning behaviors and secondly, franchisor's entrepreneurship had a significant positive effect on franchsee's boundary spanning behavior. In addition, the effects of franchisor's promise(${\beta}$=0.168) and threat(${\beta}$=-0.075) on franchisee's boundary spanning behaviors were found to be partially moderated by franchisor's entrepreneurship. Franchisees wanted franchisors to execute a high level of entrepreneurship and deliver a promise in an influence strategy. Limitations and future research directions were also discussed.

• Korean Chemical Engineering Research
• /
• v.51 no.4
• /
• pp.493-499
• /
• 2013

For the purpose of utilizing fly ash from gasification of low rank coal, we performed the series of experiments such as pyrolysis and char-$CO_2$ gasification on fly ash by using the thermogravimetric analyzer (TGA) at non-isothermal heating conditions (10, 20 and $30^{\circ}C/min$). Pyrolysis rate has been analyzed by Kissinger method as a first order, the reliability of the model was lower because of the low content of volatile matter contained in the fly ash. The experimental results for the fly ash char-$CO_2$ gasification were analyzed by the shrinking core model, homogeneous model and random pore model and then were compared with them for the coal char-$CO_2$ gasification. The fly ash char (LG coal) with low-carbon has been successfully simulated by the homogeneous model as an activation energy of 200.8 kJ/mol. In particular, the fly ash char of KPU coal with high-carbon has been successfully described by the random pore model with the activation energy of 198.3 kJ/mol and was similar to the behavior for the $CO_2$ gasification of the coal char. As a result, the activation energy for the $CO_2$ gasification of two fly ash chars don't show a large difference, but we can confirm that the models for their $CO_2$ gasification depend on the amount of fixed carbon.

• Journal of the Korean Chemical Society
• /
• v.53 no.6
• /
• pp.717-726
• /
• 2009

Multivariate models were developed for the simultaneous spectrophotometric determination of copper (II), nickel (II) and zinc (II) in water with 1-(2-thiazolylazo)-2-naphthol as chromogenic reagent in the presence of Triton X-100. To overcome the drawback of spectral interferences, principal component regression (PCR) and partial least square (PLS) multivariate calibration approaches were applied. Performances were validated with several test sets, and their results were then compared. In general, no significant difference in analytical performance between PLS and PCR models. The root mean square error of prediction (RMSEP) using three components for $Cu^{2+}$, $Ni^{2+}$ and $Zn^{2+}$ were 0.018, 0.010, 0.011 ppm, respectively. Figures of merit such as sensitivity, analytical sensitivity, limit of detection (LOD) were also estimated. High reliability was achieved when the proposed procedure was applied to simultaneous determination of $Cu^{2+}$, $Ni^{2+}$ and $Zn^{2+}$ in synthetic mixture and tap water.

• Management & Information Systems Review
• /
• v.31 no.3
• /
• pp.271-305
• /
• 2012

Due to the growing activity of online communities recently, its influence is gradually growing. Furthermore, it also has a huge effect on corporations in establishing their marketing strategy. One important aspect that occurs is that there is a high possibility that the interest of online community members, which was first organized because of a common interest, will be similar. Thus, there is a growing desire to share information and knowledge that would be mutually useful among them. Therefore, this study aims at revealing the motivation factors on why such knowledge sharing behavior occurs among online community members that are voluntarily organized. The detailed objectives of this survey is to first conduct qualitative research on online community members, and then to examine what are the motivation factors that cause knowledge sharing behavior among online community members. Second, by developing questionnaires according to the analyzed contents of the qualitative research results, the reliability and feasibility of such questions are to be verified. As a result, new motivation factor of knowledge sharing which was not suggested in the existing studies because of characteristics of online community was revealed. If the results of existing related studies and those of this study are compared, the six factors such as desire of showing off, awareness, perceived benefits, pleasure, challenge and sense of belonging except for motivator such as sense of achievement and compensation, trust are newly discovered motivators of knowledge sharing behavior.

• Journal of Digital Convergence
• /
• v.13 no.9
• /
• pp.39-47
• /
• 2015

The purpose of this study is, targeting 88 students in the department of English education for Children, D University, to examine the relationships between self-esteem, major satisfaction, career identity, and university life adjustment. A survey was performed, and collected questionnaires were analyzed with IBM SPSS Statistics 22 using reliability analysis, factorial analysis, frequency analysis, descriptive statistics, t-test, variance analysis, correlation and multiple regression analysis. As a result of the analysis, self-esteem, career identity, major satisfaction and career identity had high correlations with university life adjustment, in order. Self-esteem (${\beta}=.664$, p=.000) and major satisfaction(${\beta}=.349$, p=.000) influenced university life adjustment. In order to raise the university life adjustment ability of students in the department of English education for children, it is needed to develop systematic and specific programs for improving self-esteem and major satisfaction.

• Journal of Digital Convergence
• /
• v.11 no.7
• /
• pp.271-279
• /
• 2013

This study has significance in terms of its intent to contribute to the increase in hospital revisits by proposing measures to enhance name awareness through an examination of the relationship between the name awareness of public medical institutions and patients' revisit, and its corresponding influences. The study findings were drawn by employing analysis methods such as frequency analysis, reliability and exploratory factor analysis, t-tests, ANOVA, correlation analysis, and hierarchical multiple regression analysis. The results of the correlation analysis showed statistically significant correlations between all independent variables and the patients' revisit or not. The perception of service quality and the environmental factor of medical treatment increased the explanatory power of independent variables, thereby exhibiting a high correlation with the revisit to medical institutions. The usual image, medical service, and medical treatment environment were revealed to have a positive influence on the patient's intent to revisit. This study could confirm a correlation between the name awareness of medical public institutions and the patients' revisit or not. Consequently, to improve the quality and infrastructure of their medical services, public medical institutions are required to perform studies on measures to increase the revisits of patients by identifying their image, medical services, and treatment environment on a consistent basis.

• Journal of Digital Convergence
• /
• v.13 no.1
• /
• pp.49-66
• /
• 2015

The increase of social interest for the e-Learning industry leads to the increase of e-learning contents and the system providers which are targeted at private education companies and public institutions. As the e-Learning is used in various areas, the evaluation for evaluation criteria and suitability are needed to provide a high-quality service and reliability. Previous works suggested the evaluation criteria for quality certification, however, the technical evaluation criteria are not provided. In this paper, we suggest the technical evaluation criteria for quality certification of e-Learning contents and describe the detailed features. Through the proposed work, we can establish the technical evaluation criteria and suggest detailed evaluation items for them by providing examples. It is expected that the proposed study is able to be utilized in e-Learning industry, if the policy is reflected and notified according to the feedback of the results of the trial service.

• Journal of Digital Convergence
• /
• v.13 no.5
• /
• pp.213-218
• /
• 2015

In parallel with evolving information communication technology, M2M(Machine-to-Machine) industry has implemented multi-functional and high-performance systems, and made great strides with IoT(Internet of Things) and IoE(Internet of Everything). Authentication, confidentiality, anonymity, non-repudiation, data reliability, connectionless and traceability are prerequisites for communication security. Yet, the wireless transmission section in M2M communication is exposed to intruders' attacks. Any security issues attributable to M2M wireless communication protocols may lead to serious concerns including system faults, information leakage and privacy challenges. Therefore, mutual authentication and security are key components of protocol design. Recently, secure communication protocols have been regarded as highly important and explored as such. The present paper draws on hash function, random numbers, secret keys and session keys to design a secure communication protocol. Also, this paper tests the proposed protocol with a formal verification tool, Casper/FDR, to demonstrate its security against a range of intruders' attacks. In brief, the proposed protocol meets the security requirements, addressing the challenges without any problems.

• Journal of the Institute of Electronics Engineers of Korea SD
• /
• v.39 no.11
• /
• pp.14-23
• /
• 2002

Two implementation methods for SOVA (Soft Output Viterbi Algorithm)of Turbo decoder are applied and verfied. The first method is the combination of a trace back (TB) logic for the survivor state and a double trace back logic for the weight value in two-step SOVA. This architecure of two-setp SOVA decoder allows important savings in area and high-speed processing compared with that of one-step SOVA decoding using register exchange (RE) or trace-back (TB) method. Second method is adjusting the reliability value with a scaling factor between 0.25 and 0.33 in order to compensate for the distortion for a rate 1/3 and 8-state SOVA decoder with a 256-bit frame size. The proposed schemes contributed to higher SNR performance by 2dB at the BER 10E-4 than that of SOVA decoder without a scaling factor. In order to verify the suggested schemes, the SOVA decoder is testd using Xillinx XCV 1000E FPGA, which runs at 33.6MHz of the maximum speed with 845 latencies and it features 175K gates in the case of 256-bit frame size.