• Korean Journal of Materials Research
• /
• v.9 no.4
• /
• pp.373-377
• /
• 1999

The cure mechanicsm and cure kinetics of diglycidyl ether of bisphenol A(DGEBA)/4,4'-methylene dianiline(MDA)/nitrile(MN, SN, GN) systems were studied by FT-IR and DSC to develop new applications in the biomedical polymer fields. The network structure of the DGEBA/MDA system was changed to the chain-extended network structure by the addition of nitriles. The reactions contributed to the chain extension were the primary amine-nitrile and hydroxyl-nitrile reactions. The chain-extended network structure could be indirectly proved by the decrement of T\ulcorner and the increment of impact strength with the increasing nitrile content. The cure rate of DGEBA/MDA/nitrile system was lower than that of DGEBA/MDA system due to the disturbance of nitrile group in the reaction of primary amine and epoxide groups.

• Information and Communications Magazine
• /
• v.20 no.11
• /
• pp.1550-1559
• /
• 2003

The convergence of fixed and wireless networks in data communication is providing the necessary driver for M2M commerce to take-off. The opportunities provided by M2M Commerce areonly limited by imagination. Automotive Fleet and Freight, Tolling, Water and Power Metering, Supply Chain Management including Asset Management, Remote Monitoring and Diagnostics, Energy Management and Access Control and Security are among the many M2M applications that are currently getting rolled out. ARC Group expects the worldwide solutions market to be worth in excess of US$ 100 billion by 2007. In addition, operator revenues worldwide from the transport of Telematics data alone will rise from US$ 3.5 billion in 2002 to US$ 78 billion by 2007. This paper discusses some of the lifestyle and business opportunities provided by M2M Commerce in the new ear of network convergence. It also provides some case studies to demonstrate the benefits of M2M Commerce across the supply chain. The key focus of the paper is on achieving enhanced lifestyle, cost reduction, improved profitability and enhanced customer relationship management through M2M Commerce.

• Journal of the Korea Safety Management & Science
• /
• v.12 no.4
• /
• pp.153-160
• /
• 2010

In this paper, effects of information sharing in multi-level supply chain management have been studied through simulation. The simulation model consists of a manufacturing company as a center, three suppliers, two logistic centers, and three different retail supply lines of each logistics centers. The mathematical model and the simulation were developed when real-time information sharing occurs and does not occur in supply chain under the assumption that each company applies (s, S) inventory policies. In addition, this paper analyzed the effects of the change of variables related to total costs, which compose of total ordering cost, total transportation cost, total carrying cost and shortage cost that are caused by the change of demand of three different patterns with the way of information sharing.

• Communications for Statistical Applications and Methods
• /
• v.25 no.1
• /
• pp.29-42
• /
• 2018

We combine the integer-valued GARCH(1, 1) model with a generalized regime-switching model to propose a dynamic count time series model. Our model adopts Markov-chains with time-varying dependent transition probabilities to model dynamic count time series called the generalized regime-switching integer-valued GARCH(1, 1) (GRS-INGARCH(1, 1)) models. We derive a recursive formula of the conditional probability of the regime in the Markov-chain given the past information, in terms of transition probabilities of the Markov-chain and the Poisson parameters of the INGARCH(1, 1) process. In addition, we also study the forecasting of the Poisson parameter as well as the cumulative impulse response function of the model, which is a measure for the persistence of volatility. A Monte-Carlo simulation is conducted to see the performances of volatility forecasting and behaviors of cumulative impulse response coefficients as well as conditional maximum likelihood estimation; consequently, a real data application is given.

• Journal of Korea Society of Industrial Information Systems
• /
• v.26 no.5
• /
• pp.37-54
• /
• 2021

In this study, a customized model (CM) for the efficient operation of cold chain logistics considering the hypergeometric distribution is proposed. The CM focuses on the segmentation market of ready-to-eat foods and juices made from fresh materials. Companies should determine the amount of production by predicting consumer preferences and quantity to ensure high-efficiency production. The CM is represented as a mathematical formulation and implemented using the genetic algorithm (GA). Addition, the relative weights of CM are calculated. Further, the calculated weights are applied to the GA. In the numerical experiment, hypergeometric distribution is used to calculate the relative weights between the range of production quantities and the customized amount. Experiment results are the values of relative weights and the comparison results by average values of handling cost, total cost and CPU time. Finally, the significance of this study is summarized and a future research direction is remarked in conclusion.

• Electronics and Telecommunications Trends
• /
• v.33 no.6
• /
• pp.139-153
• /
• 2018

The explosive interest in block chain, which was triggered by Bitcoin in 2009, is leading to substantial investment and the development of block chain technology. There is no dispute among experts that block chain will be the next generation of innovation. However, despite the high expectations for block chains, the related technology still has certain limitations. In addition to improving issues such as a low transaction throughput, inefficient agreement algorithms, and an inflexible governance structure, it is necessary to solve various problems for commercialization and full-scale spreading owing to the trilemma problem among the scalability, security, and decentralization. Under this situation, identification of the technology characteristics according to the generation is helpful for the development of the core technology requirements and commercialization blueprint in establishing an R&D direction. Therefore, in this article, the development of blockchain technology is divided into generations and analyzed in terms of the operational structure, consensus algorithm, governance, scalability, and security.

• Journal of Microbiology and Biotechnology
• /
• v.33 no.7
• /
• pp.849-856
• /
• 2023

Short-chain fatty acids (SCFAs), such as butyrate, propionate, and acetate produced by the gut microbiota have been implicated in physiological responses (defense mechanisms, immune responses, and cell metabolism) in the human body. In several types of cancers, SCFAs, especially butyrate, suppress tumor growth and cancer cell metastasis via the regulation of the cell cycle, autophagy, cancer-related signaling pathways, and cancer cell metabolism. In addition, combination treatment with SCFAs and anticancer drugs exhibits synergistic effects, increasing anticancer treatment efficiency and attenuating anticancer drug resistance. Therefore, in this review, we point out the importance of SCFAs and the mechanisms underlying their effects in cancer treatment and suggest using SCFA-producing microbes and SCFAs to increase therapeutic efficacy in several types of cancers.

• Asian-Australasian Journal of Animal Sciences
• /
• v.27 no.3
• /
• pp.414-421
• /
• 2014

This study was conducted to determine the effects of saturated long-chain fatty acids (LCFA) on cell proliferation and triacylglycerol (TAG) content, as well as mRNA expression of ${\alpha}s1$-casein (CSN1S1) and genes associated with lipid and protein synthesis in bovine mammary epithelial cells (BMECs). Primary cells were isolated from the mammary glands of Holstein dairy cows, and were passaged twice. Then cells were cultured with different levels of palmitate or stearate (0, 200, 300, 400, 500, and 600 ${\mu}M$) for 48 h and fetal bovine serum in the culture solution was replaced with fatty acid-free BSA (1 g/L). The results showed that cell proliferation tended to be increased quadratically with increasing addition of stearate. Treatments with palmitate or stearate induced an increase in TAG contents at 0 to 600 ${\mu}M$ in a concentration-dependent manner, and the addition of 600 ${\mu}M$ was less effective in improving TAG accumulation. The expression of acetyl-coenzyme A carboxylase alpha, fatty acid synthase and fatty acid-binding protein 3 was inhibited when palmitate or stearate were added in culture medium, whereas cluster of differentiation 36 and CSN1S1 mRNA abundance was increased in a concentration-dependent manner. The mRNA expressions of peroxisome proliferator-activated receptor gamma, mammalian target of rapamycin and signal transducer and activator of transcription 5 with palmitate or stearate had no significant differences relative to the control. These results implied that certain concentrations of saturated LCFA could stimulate cell proliferation and the accumulation of TAG, whereas a reduction may occur with the addition of an overdose of saturated LCFA. Saturated LCFA could up-regulate CSN1S1 mRNA abundance, but further studies are necessary to elucidate the mechanism for regulating milk fat and protein synthesis.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2008.11a
• /
• pp.813-816
• /
• 2008

Polycarboxylate-type superplasticizer is widely used for producing self-compacting and high-strength concrete and improving concrete durability. This paper discusses the influence of molecular structure of polycarboxylate-type superplasticizer on the fluidity and the rate of heat liberation of ordinary Portland cement paste. The fluidity of cement paste was increased by addition of polycarboxylate-type superplasticizer. The arrival time up to the maximum rate of heat liberation was increased by addition of polycarboxylate-type superplasticizer. The fluidity and the arrival time up to the maximum rate of heat liberation were more influenced by addition of polycarboxylate-type superplasticizer having shorter grafted chain than that having longer grafted chain.

• Asian-Australasian Journal of Animal Sciences
• /
• v.18 no.7
• /
• pp.1041-1047
• /
• 2005

This study was carried out to investigate the changes of chemical and sensory properties and cholesterol lowering effect of milk treated with $\beta$-cyclodextrin to reduce cholesterol and supplemented with evening primrose oil (EPO). The average cholesterol removal rate was 93.5%. The thiobarbituric acid (TBA) absorbance increased proportionally to storage period and amount of EPO addition. TBA absorbance was significantly different in the EPO-added groups from that in unadded groups in all periods. The production of short-chain free fatty acids (FFA) increased with longer period of storage. From 6 days of storage, the amounts of short-chain FFA in 6 and 10% EPO-added groups were significantly different from other groups. The scores for all sensory characteristics indicated that sensory quality decreased with both storage time and increasing amount of EPO. Oxidative off-flavor and off-taste were more intense with higher amounts of EPO addition and longer storage period. Also, the higher the amount of EPO addition, the lower overall scores throughout the 15 day storage. Feeding 10% EPO-supplemented cholesterol-reduced milk increased high density lipoprotein (HDL) in male Sprague-Dawley rats by 76%, which is significantly different from the control (27%).