• Applied Chemistry for Engineering
• /
• v.29 no.3
• /
• pp.270-277
• /
• 2018

The adsorption of Eosin Y by the activated carbon (WCAC) prepared from waste citrus peel was investigated by using response surface methodology (RSM) and Box-Behnken design (BBD) statistical procedures. Experiments were carried out as per BBD with three input parameters, the Eosin Y concentration (Conc. : 30~50 mg/L), the solution temperature (Temp. : 293~313 K), and the adsorbent dose (Dose : 0.05~0.15 g/L). Regression analysis showed a good fit of the experimental data to the second-order polynomial model with coefficients of the determination ($R^2$) value of 0.9851 and P-value (Lack of fit) of 0.342. An optimum dye uptake of 59.3 mg/g was achieved at the dye concentration of 50 mg/L, the temperature of 333 K, and the adsorbent dose of 0.1056 g. The adsorption process of Eosin Y by WCAC can be well described by the pseudo second order kinetic model. The experimental data followed the Langmuir isotherm model.

• Korean Journal of Cognitive Science
• /
• v.10 no.4
• /
• pp.71-83
• /
• 1999

Conventional symbolic inference systems lack flexibility because they do not well reflect flexible semantic structure of knowledge and use symbolic logic for their basic inference mechanism. For solving this problem. we have recently proposed the 'Connectionist Semantic Network(CSN)' as a model for flexible knowledge representation and inference based on neural networks. The CSN is capable of carrying out both approximate reasoning and commonsense reasoning based on similarity and association. However. we have difficulties in representing general and structured high-level knowledge and variable binding using the connectionist framework of the CSN. In this paper. we propose a hybrid system called SymCSN(Symbolic CSN) that combines a symbolic module for representing general and structured high-level knowledge and a connectionist module for representing and learning low-level semantic structure Simulation results show that the SymCSN is a plausible model for human-like flexible knowledge representation and inference.

• Journal of the Korea Convergence Society
• /
• v.8 no.8
• /
• pp.307-314
• /
• 2017

The Purpose of this study was to identify the level of learned helplessness and the relationship among variables affecting their learned helplessness. We have carried out research on 799 students. and collected data were analyzed using t-test, ANOVA, scheffe test, pearson's correlation coefficient. As a result, the mean score of learned helplessness was 2.55 (${\pm}.61$), Of the sub-domains, 'lack of control' was the highest with 2.85 (${\pm}.44$). And It was found that the helplessness was high in the case of poor fellowship, low academic achievement and poor family cooperation. These results were significantly correlated. Through the follow-up research, it is necessary to carry out management to reduce the learned helplessness by developing differentiated program that can reduce the learned helplessness of university students by identifying variables that can explain the learned helplessness of university students.

• Journal of the Korean Society for Marine Environment & Energy
• /
• v.13 no.4
• /
• pp.249-262
• /
• 2010

Regulatory test method for Total Petroleum Hydrocarbons (TPHs) in the marine sediment and biota has not still been established even though TPHs are one of the major pollutants in marine environment. Based on the Korean Soil Standard Method (SSM) for TPHs, we considered a new treatment method for determining TPHs in marine environmental samples by using a Gas chromatography coupled with Mass spectrometric detector. We suggested an improved recovery test for quality control procedures and introduced analytical procedures of removing sulfur, polar organic materials, water and saponification for removing neutral lipids in marine bottom sediments and biota.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.28 no.11B
• /
• pp.1038-1049
• /
• 2003

Exactly measuring traffic load is the basis for efficient traffic engineering. However, precise traffic measurement involves inspecting every packet traversing a lint resulting in significant overhead on routers with high-speed links. Sampling techniques are proposed as an alternative way to reduce the measurement overhead. But, since sampling inevitably accompany with error, there should be a way to control, or at least limit, the error for traffic engineering applications to work correctly. In this paper, we address the problem of bounding sampling error within a pre-specified tolerance level. We derive a relationship between the number of samples, the accuracy of estimation and the squared coefficient of variation of packet size distribution. Based on this relationship, we propose an adaptive random sampling technique that determines the minimum sampling probability adaptively according to traffic dynamics. Using real network traffic traces, we show that the proposed adaptive random sampling technique indeed produces the desired accuracy, while also yielding significant reduction in the amount of traffic samples.

• Journal of Convergence for Information Technology
• /
• v.8 no.1
• /
• pp.123-130
• /
• 2018

The subjects of this study were municipal citizens of Gyeongsangbuk-do Province and selected 250 members of the sports clubs as members. The sampling method for the data was used with simple ramdom sampling method, self-administration method. After questionnaire was distributed and retrieved, a total of 200 questionnaires were analyzed except for 50 items which were judged to be lack of credibility (double entry, no entry, insufficient data). For the data analysis, frequency analysis, ${\chi}^2$, factor analysis, reliability analysis, and one-way ANOVA were conducted in this study. First, there was no significant difference in life satisfaction among the participants. However, there was a significant difference in leisure satisfaction according to age. Second, there was a statistically significant difference in the life satisfaction of the athletes according to educational background, and there was a statistically significant difference in leisure satisfaction according to educational background.

• Korean Journal of Microbiology
• /
• v.23 no.1
• /
• pp.9-12
• /
• 1985

As a part of the host cell development for a amplified recombinant trp operon, $aroP^-$ mutation was introduced in a E. coli host strain. $aroP^-$ mutation was induced by transposon Tn10 and transduced into the E. coli host cell by bacteriophage P1Kc. The effect of $aroP^-$ mutation on the excretion of tryptophan in E. coli $trpR^{-ts}/ColE_1 -trp^+$ cells was investigated. Mutant lacking the general aromatic transport system was resistant to ${\beta}-2-thienylalanine\;(2{\times}10^{-4}\;M)$, p-fluorophenylalanine $(2{\times}10^{-4}M)$, or 5-methyltryptophan $(2{\times}10^{-4}\;M.)[^3H]-tryptophan$ uptake of the $aroP^-$ mutant strain was reduced considerably as compared with $aroP^+$ counterpart. The rate of $[^3H]-tryptophan$ uptake of the $aroP^-$ mutant strain treated with $NaN_3(3{\times}10^{-2}\;M)$ was much less affected than that of $aroP^+$ counterpart. The $aroP^-$ transductants increased the tryptophan excretion from E. coli $trpR^{-ts}/ColE_1 -trp^+$ four times more than $aroP^+$ counterpart.

• Journal of the Korea Society of Computer and Information
• /
• v.15 no.10
• /
• pp.183-190
• /
• 2010

The present study attempted to identify the metacognitive strategies used by L2 writers at the university level as well as their particular aspects which might influence the use of these strategies. Twenty-seven participants, all of whom were enrolled in an English course, were asked to write an expository essay and then complete a questionnaire which includes their beliefs and attitudes toward L2 writing experience and the metacognitive strategies during the writing process. It was found that even though inexpert writers knew and employed as many strategies as the expert counterparts did, they were unsuccessful in the quality of their texts. Simply possessing a repertoire of metacognitive strategies was not enough for successful L2 writing. The failure of the inexpert writers to apply these metacognitive strategies in an effective manner was influenced by affective factors such as anxiety, self-confidence, self-concept, etc. As a result of this study, a pedagogical implication is suggested.

• Journal of the Korea Society of Computer and Information
• /
• v.3 no.2
• /
• pp.1-6
• /
• 1998

The evaluation of reliability is very important in the development process of software. There may be lack of trustfulness on the results that come from the analysis and evaluation of reliability of softwares which do not divide the test phases. At this point, this article studies how to evaluate the reliability dividing the test phases in order to settle the these problems. In doing so, I apply the fault data to be found in Unit Test, Integration Test, Validation Test and System Test to SRGM(Software Reliability Growth Model), Exponential SRGM, Delayed S-shaped SRGM and Inflection S-shaped SRGM. The result is that Inflection S-shaped is best suitable with Unit Test Delayed S-shaped is best suitable with Integration and Validation Test, and Exponential SRGM is best suitable with System test. In this respect, I can show that the results of this study on parameter estimation, difference square summation, number of fault remained is superior to the established methods.

• Korean Chemical Engineering Research
• /
• v.48 no.4
• /
• pp.457-461
• /
• 2010

After the industrial revolution, quantity production system has made the life of mankind rich and to fulfill the consumer's desire competitive power of the enterprise constantly make has made effort in quality, price and engineering department not remaining simple manufactures. But in such a change production lacked safety. Consequently, the main study studied in return domestic organization which produces a chemistry fiber rope to be used fact vessel or as a athletic equipment safety countermeasure. One of the assesment method on product liability, Checklist is showed that It can be used not as an evaluation but as a development factor of company. Also, checklist that used a study could expect that assist the company of management structure as well as improvement of product safety.