• Proceedings of the Korea Society for Simulation Conference
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• 2000.11a
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• pp.34-40
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• 2000

통합 생산시스템의 성능평가문제는 많은 요소들이 고려되어야하며 수리모델을 위하여 많은 가정사항들이 주어진다. 실제 제생산시스템의 운영환경을 고려한 성능평가를 위하여 Simulation Model들이 많이 연구되어 오고있으나, 실제 활용의 용이성 및 관련 data 및 출력의 이해가 실무자들에게는 매우 어려운 문제로 남아 있다 본 연구에서는 사용자의 요구 수준과 System의 환경 여건에 따른 각종 Simulation Model들을 비교 조사 연구하여 수요자의 요구와 System의 특성에 적절한 방법을 활용할 수 있도록 하였다. 본 연구에 다음과 같은 Simulation Model들을 비교 연구하였다 : 1) CAN-WIP Model, 2) RAM-Cost Model, 3) FACTOR/AIM 응용, 및 4) AutoMod의 응용, 본 연구에 고려된 Simulation Model들의 관련 응용 Program을 개발하고 Sample 예제를 통하여 결과를 비교 분석하였다.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.37 no.4
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• pp.63-71
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• 2014

As power consumption increases, more power utilities are required to satisfy the demand and consequently results in tremendous cost to build the utilities. Another issue in construction of power utilities to meet the peak demand is an inefficiency caused by surplus power during non-peak time. Therefore, most power company considers power demand management with time-based electricity rate policy which applies different rate over time. This paper considers an optimal machine operation problem under the time-based electricity rates. In TOC (Theory of Constraints), the production capacities of all machines are limited to one of the bottleneck machine to minimize the WIP (work in process). In the situation, other machines except the bottleneck are able to stop their operations without any throughput loss of the whole manufacturing line for saving power utility cost. To consider this problem three integer programming models are introduced. The three models include (1) line shutdown, (2) block shutdown, and (3) individual machine shutdown. We demonstrate the effectiveness of the proposed IP models through diverse experiments, by comparing with a TOC-based machine operation planning considered as a current model.

• Korean Chemical Engineering Research
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• v.49 no.6
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• pp.697-703
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• 2011

Capacitive deionization(CDI) is an ion removal technology that employs the basic electrochemical principle of absorbing ions in high surface area electrode. CDI technology reduce power consumption because it operates at lower electrode potential(about 1~2 V). Also, it is an environmentally friendly technology because no acid, base, or salts are required to generate the surface. In this study, we searched the patents and papers to investigate the trend of CDI technologies. Database was collected from WIPS and Scopus site and was investigated according to electrode, module and application technology of CDI. The technology trend of CDI was analyzed based on patent application year, countries, main applications and technologies.

• Journal of Information Processing Systems
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• v.15 no.1
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• pp.181-188
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• 2019

A production system is a management system that supports all activities to perform production operations at the manufacturing site. From the point-of-view of a smart factory, smart manufacturing systems redesigned the concept of onsite production systems to fit the entire system and its necessary functional composition. In this study, we select the key functions needed to build a smart factory for a PCB line and propose a new six-step model for the deployment of a smart manufacturing system by integrating essential functions. The smart manufacturing system newly classified the production and operation tasks of PCB manufacturing and selected necessary functions through requirement analysis and benchmarking of advanced companies. The selected production operation tasks are mapped to the functions of the system and configured into seven modules, and the optimal deployment model is presented to allow flexible responses to the characteristics of the tasks. These methodologies are first presented in this study, and the proposed model was applied to the PCB line to confirm that they had significant changes in the work method, qualitative effects, and quantitative effects. Typically, lead time and WIP have reduced by about 50%.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.13
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• pp.5191-5197
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• 2015

A partial response or resistance to chemotherapeutic agents is considered as a main obstacle in treatment of patients with cancer, including breast cancer. Refining taxane-based treatment procedures using adjuvant or combination treatment is a novel strategy to increase the efficiency of chemotherapy. PPM1D is a molecule activated by reactive oxygen species. whose expression is reported to modulate the recruitment of DNA repair molecules. In this study we examined the impact of arsenic trioxide on efficacy of paclitaxel-induced apoptosis in paclitaxel-resistant MCF-7 cells. We also investigated the expression of PPM1D and TP53 genes in response to this combination treatment. Resistant cells were developed from the parent MCF-7 cell line by applying increasing concentrations of paclitaxel. MTT assays were applied to determine the rate of cell survival. DAPI staining using fluorescent microscopy was employed to study apoptotic bodies. Real-time RT-PCR analysis was also applied to determine PPM1D mRNA levels. Our results revealed that combination of arsenic trioxide and paclitaxel elevates the efficacy of the latter in induction of apoptosis in MCF-7/PAC resistant cells. Applying arsenic trioxide also caused significant decreases in PPM1D mRNA levels (p<0.05). Our findings suggest that arsenic trioxide increases paclitaxel-induced apoptosis by down regulation of PPM1D expression. PPM1D dependent signaling can be considered as a novel target to improve the efficacy of chemotherapeutic agents in resistant breast cancer cells.

• Journal of Dental Rehabilitation and Applied Science
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• v.23 no.3
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• pp.259-268
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• 2007

purpose: This study was to evaluate the shear bond strength of Lithium Disilicate Glass-Ceramic by removable method of temporary cement on the abutment tooth. Material and Method: Sixty molar teeth of human with the occlusal surface up were mounted in acrylic resin blocks. The 45 specimens were prepared to exposure dentin by diamond bur and the eugenol-containing temporary cement($Cavitec^{TM}$ ($KERR^{(R)}$, U.S.A)was applied to the dentin surfaces. After initial removal of the cement with a dental explorer, the specimens were divided into 4 groups of 15 specimens each. The dentin surfaces of the specimens were treated by rotary instrument with as follow pastes: $Zircate^{(R)}$ prophy paste(Dentsply, U.S.A), Radent Prophy Paste(Pascal company,inc. U.S.A), and Dental pumice(Wip mix corporation,U.S.A). An adhesive resin luting agent(Variolink $II^{(R)}$, Ivoclar Vivadent, Leichtenstein) including Monobond-S and $Excite^{(R)}$ was applied to all specimens. The ceramic specimens were made with an A1 ingot of IPS Empress $II^{(R)}$ (Ivoclar Vivadent, Leichtenstein). After the specimens were stored in distilled water for 48hr, the shear bond strength(MPa) was measured by a Universal testing machine(Zwick 145641, Zwick, Germany) at a 1mm/min cross-head speed. The data were statistically analyzed by one-way ANOVA and Duncan's multiple range test. Results: In all group, there were no significant differences in comparison with the control group(p>0.05). The pattern of most failure showed the mixed type of cohesive and adhesive failure. Conclusion: Resin bond strength of IPS Empress $II^{(R)}$ was not affected by removal method of the temporary cement.

• IE interfaces
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• v.25 no.2
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• pp.241-254
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• 2012

This paper studies the relationship between SCM(Supply Chain Management) metrics and corporate value (Tobin's Q) for manufacturing and wholesale/retail firms in Korea. Specifically, the multiple regression analysis is used to investigate the relationships 1) between inventory level, inventory turns, and days of inventory and Tobin's Q and 2) between cash-to-cash (C2C) cycle time including its components such as days of inventory, days sales outstanding, and days payable outstanding and Tobin's Q. The results indicate that there exist statistically significant negative relationships between inventory levels and days of inventory (DOI) and Tobin's Q. Also, we found that there exist commonly known negative correlations between days of raw materials inventory and days of work in process (WIP) inventory and Tobin's Q. For the C2C cycle time, we found that there -exists a statistically significant negative relationship between the C2C cycle time and Tobin's Q. Also, we found that there exist commonly known correlations between the two components of C2C cycle time and Tobin's Q such as the negative for DOI and days sales outstanding. This study clearly shows the negative relationship in general between inventory levels and corporate value and between C2C time and corporate value, and this kind of result has not been found by previous studies in Korea.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.65 no.2
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• pp.104-112
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• 2020

Maize is thought to be an alternative crop to rice in paddy fields for efficient field management and maintenance of rice production at appropriate levels in Korea. Thus efforts to breed waterlogging-tolerant maize cultivars have been ongoing. However, molecular studies related to waterlogging tolerance are limited for developing molecular markers to select waterlogging tolerant maize varieties. In this study, we examined molecular biological changes of B73 in the V3 stage after immersion treatment for 7 days. Overall growth of maize was lower in treated samples compared to non-immersed control samples. The length of leaf and root decreased by 21.3% and 50.6%, respectively and the weight of root reduced by 21.6%. Soil plant analysis development (SPAD) value and chlorophyll content of leaf also decreased by 55.7% and 35.3%, respectively. Reactive oxygen species (ROS) content of root increased by 46.5% at 2 hours in immersion treatment. In addition, immersed roots were 2.5-fold thickened with additional aerenchyma formation in the cortex. In order to identify the causes of these changes, we performed a microarray and found increased expression of genes, such as WIP1, PMIP2, EXPA1, TPS1, and MAS1, in immersed samples. These differentially expressed genes and expression of previously reported genes, including ALDH2, Wusl1032, UP-1, UP-2, and CAT2 were further confirmed with qRT-PCR. Here, we report 7 differentially expressed genes after immersing treatment, which may be utilized as useful resources for breeding waterlogging- tolerant maize.

• Journal of the Korean Institute of Landscape Architecture
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• v.36 no.3
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• pp.29-38
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• 2008

This study intends to analyze the value of school forests, one type of urban forest. For this purpose, four attributes of school forests were investigated, considering ecological, educational, social and economic values using a conjoint model as the stated preference. Based on literature reviews, the levels of the four attributes were selected, and a questionnaire survey was given to 279 urban residents divided into 2 groups: those impacted by school forests and those not. The study results suggest that the most important attribute of school forests is economic value, and next is ecological, social and educational value according to the part-worth model. The fitness level of the model is 0.900(total group) which is very significant. As for the economic value, free and 1,000 won are more critical factors than the other 2 levels, 5,000 won and 10,000 won and air pollution purification and making the school landscape are more critical factors than small habitats and microclimate factors. In addition, regarding the social value related to residents' leisure activities，the utility of nature observation is higher than walking and exercising. Finally, for educational value, understanding nature's importance is more critical than the emotions and learning of students. The estimated WTP per household/month is 3,580 won, the group related to school forestsis 3,650 won and the non-related group is 3,540 won. Based on these results, the estimated total economic value of all households per year is 6,820 hundred million won. The group related to school forests is 6,970 hundred million won and the non-related group is 6,750 hundred million won.