Optimal Ordering Policy of a Risk-Averse Retailer Subject to Inventory Inaccuracy

Zhu, Lijing,Hong, Ki-Sung,Lee, Chulung Hindawi Limited 2013 Mathematical problems in engineering Vol.2013 No.-

<P>Inventory inaccuracy refers to the discrepancy between the actual inventory and the recorded inventory information. Inventory inaccuracy is prevalent in retail stores. It may result in a higher inventory level or poor customer service. Earlier studies of inventory inaccuracy have traditionally assumed risk-neutral retailers whose objective is to maximize expected profits. We investigate a risk-averse retailer within a newsvendor framework. The risk aversion attitude is measured by conditional-value-at-risk (CVaR). We consider inventory inaccuracy stemming both from permanent shrinkage and temporary shrinkage. Two scenarios of reducing inventory shrinkage are presented. In the first scenario, the retailer conducts physical inventory audits to identify the discrepancy. In the second scenario, the retailer deploys an automatic tracking technology, radiofrequency identification (RFID), to reduce inventory shrinkage. With the CVaR criterion, we propose optimal policies for the two scenarios. We show monotonicity between the retailer’s ordering policy and his risk aversion degree. A numerical analysis provides managerial insights for risk-averse retailers considering investing in RFID technology.</P>

Thermal Conduction in Transparent Carbon Nanotube Films

Lijing Zhu,Duckjong Kim 한국진공학회 2012 한국진공학회 학술발표회초록집 Vol.2012 No.2

Simotang Alleviates the Gastrointestinal Side Effects of Chemotherapy by Altering Gut Microbiota

( Lijing Deng ),( Xingyi Zhou ),( Zhifang Lan ),( Kairui Tang ),( Xiaoxu Zhu ),( Xiaowei Mo ),( Zongyao Zhao ),( Zhiqiang Zhao ),( Mansi Wu ) 한국미생물생명공학회 2022 Journal of microbiology and biotechnology Vol.32 No.4

Simotang oral liquid (SMT) is a traditional Chinese medicine (TCM) consisting of four natural plants and is used to alleviate gastrointestinal side effects after chemotherapy and functional dyspepsia (FD). However, the mechanism by which SMT helps cure these gastrointestinal diseases is still unknown. Here, we discovered that SMT could alleviate gastrointestinal side effects after chemotherapy by altering gut microbiota. C57BL/6J mice were treated with cisplatin (DDP) and SMT, and biological samples were collected. Pathological changes in the small intestine were observed, and the intestinal injury score was assessed. The expression levels of the inflammatory factors IL-1β and IL-6 and the adhesive factors Occludin and ZO-1 in mouse blood or small intestine tissue were also detected. Moreover, the gut microbiota was analyzed by high-throughput sequencing of 16S rRNA amplicons. SMT was found to effectively reduce gastrointestinal mucositis after DDP injection, which lowered inflammation and tightened the intestinal epithelial cells. Gut microbiota analysis showed that the abundance of the anti-inflammatory microbiota was downregulated and that the inflammatory microbiota was upregulated in DDP-treated mice. SMT upregulated antiinflammatory and anticancer microbiota abundance, while the inflammatory microbiota was downregulated. An antibiotic cocktail (ABX) was also used to delete mice gut microbiota to test the importance of gut microbiota, and we found that SMT could not alleviate gastrointestinal mucositis after DDP injection, showing that gut microbiota might be an important mediator of SMT treatment. Our study provides evidence that SMT might moderate gastrointestinal mucositis after chemotherapy by altering gut microbiota.

Macrodispersion of multi-walled carbon nanotubes for conductive films.

Kim, Duckjong,Zhu, Lijing,Kim, Jae-Hyun,Han, Chang-Soo,Baik, Seunghyun American Scientific Publishers 2012 Journal of Nanoscience and Nanotechnology Vol.12 No.4

<P>Understanding of the effect of the multi-walled carbon nanotube (MWCNT) dispersion process on physical properties of MWCNT film is crucial in process optimization of MWCNT film-based products. In the present work, the electrical conduction property of MWCNT films according to various conditions in MWCNT dispersion is investigated. Spectroscopic analysis of dispersed MWCNTs show that the electrical resistance of the MWCNT conductive film is affected by an increase in the electrical contacts between adjacent CNTs due to CNT debundling and physical damage caused by ultrasonic processing. Based on the two conflicting parameters, dispersion guidelines for highly conductive MWCNT film are presented.</P>

Raman Characterization of Thermal Conduction in Transparent Carbon Nanotube Films

Kim, Duckjong,Zhu, Lijing,Han, Chang-Soo,Kim, Jae-Hyun,Baik, Seunghyun American Chemical Society 2011 Langmuir Vol.27 No.23

<P>Using materials with high thermal conductivity is a matter of great concern in the field of thermal management. In this study, we present our experimental results on two-dimensional thermal conductivity of carbon nanotube (CNT) films obtained by using an optical method based on Raman spectroscopy. We use four kinds of CNTs in film preparation to investigate the effect of CNT type on heat spreading performance of CNT films. This first comparative study using the optical method shows that the arc-discharge single-walled carbon nanotubes yield the best heat spreading film. We also show that the Raman method renders reasonable thermal conductivity value as long as the sample is a transparent film by testing CNT films with various transmittance. This study provides useful information on characterization of thermal conduction in transparent CNT films and could be an important step toward high-performance carbon-based heat spreading films.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/langd5/2011/langd5.2011.27.issue-23/la203007y/production/images/medium/la-2011-03007y_0007.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/la203007y'>ACS Electronic Supporting Info</A></P>

Heat Spreading in Carbon Nanotube Films

김덕종(Duckjong Kim),주려청(Lijing Zhu),한창수(Chang-Soo Han),백승현(Seunghyun Baik) 대한기계학회 2011 대한기계학회 춘추학술대회 Vol.2011 No.5

Dimensional dependence of phonon transport in freestanding atomic layer systems.

Kim, Duckjong,Hwangbo, Yun,Zhu, Lijing,Mag-Isa, Alexander E,Kim, Kwang-Seop,Kim, Jae-Hyun RSC Pub 2013 Nanoscale Vol.5 No.23

<P>Due to the fast development of nanotechnology, we have the capability of manipulating atomic layer systems such as graphene, hexagonal boron nitride and dichalcogenides. The major concern in the 2-dimensional nanostructures is how to preserve their exceptional single-layer properties in 3-dimensional bulk structures. In this study, we report that the extreme phonon transport in graphene is highly affected by the graphitic layer stacking based on experimental investigation of the thermal conduction in few-layer graphene, 1-7 layers thick, suspended over holes of various diameters. We fabricate freestanding axisymmetric graphene structures without any perturbing substrate, and measure the in-plane transport property in terms of thermal conduction by using Raman spectroscopy. From the difference in susceptibility to substrate effect, size effect on hot-spot temperature variation and layer number dependence of thermal conductivity, we show that the graphitic membranes with 2 or more layers have characteristics similar to 3-dimensional graphite, which are very different from those of 2-dimensional graphene membranes. This implies that the scattering of out-of-plane phonons by interlayer atomic coupling could be a key mechanism governing the intrinsic thermal property.</P>

Preprocessing of Carbon Nanotube Dispersion for Productive Spray Coating

Duckjong Kim(김덕종),Lijing Zhu(주려청) 대한기계학회 2012 대한기계학회 춘추학술대회 Vol.2012 No.11

Several methods have been proposed and used for the fabrication of thin films of carbon nanotubes (CNTs). Among them, the spray coating method is a robust approach for large area fabrication, but clogging in the spray nozzle is a critical problem hindering stable and controlled coating process. In this study, we investigate the effect of exsitance of microparticles in the multi-walled CNT (MWCNT) solution on the clogging problem. We checked repeatability in the flow rate through the spray nozzle using various CNT solutions with different average particle number. We also checked the effect of the particle number on the concentration and stability of the CNT solution. From the experimental data, we found that 2 min-centrifugation is appropriate in the process of MWCNT solution preparation for stable and productive spray process.

Mediation analysis of leisure activities on the association between cognitive function and mortality: a longitudinal study of 42,942 Chinese adults 65 years and older

Xingxing Chen,Wenfan Wu,Xian Zhang,Tingxi Long,Wenyu Zhu,Rundong Hu,Xurui Jin,Lijing L. Yan,Yao Yao 한국역학회 2022 Epidemiology and Health Vol.44 No.-

study aimed to evaluate whether leisure activities causally mediate these associations. METHODS This longitudinal study included 42,246 participants aged over 65 years from the Chinese Longitudinal Healthy Longevity Survey. The Mini-Mental State Examination and a self-reported scale were used to measure cognitive status and leisure activities, respectively. We examined the associations of cognitive function and leisure activities with mortality using Cox proportional hazards models. Causal mediation analysis was used to assess whether leisure activities mediated the association between cognitive function and mortality. RESULTS Cognitive function and leisure activities were inversely associated with mortality. Leisure activities accounted for 28.3% (95% confidence interval [CI], 25.6 to 31.1) of the total effect of cognitive function and mortality. A higher mediated proportion (PM) was observed for physical leisure activities (PM, 20.1%; 95% CI, 18.0 to 22.3) than for social leisure activities (PM, 17.7%; 95% CI, 15.7 to 19.7). The mediating effect was higher among participants at younger ages (PM, 41.5%; 95% CI, 21.3 to 65.4), those with higher education levels (PM, 30.5%; 95% CI, 25.3 to 36.2), and residents of rural China (PM, 42.5%; 95% CI, 25.4 to 62.5). CONCLUSIONS Cognitive function was associated with inverse mortality. Leisure activities significantly mediated this association. Participation in leisure activities at the early stages of mild cognitive impairment could reduce the risk of mortality, which has a major impact on interventional strategies for healthy aging.

Mediation analysis of leisure activities on the association between cognitive function and mortality: longitudinal study of 42,942 Chinese adults 65 years and older

Chen Xingxing,Zhang Xian,Long Tingxi,Wu Wenfan,Hu Rundong,Jin Xurui,Yan Lijing L,Yao Yao,Wenyu Zhu 한국역학회 2022 Epidemiology and Health Vol.44 No.-

OBJECTIVES: Previous studies have established associations of cognitive function and leisure activities with mortality. This study aimed to evaluate whether leisure activities causally mediate these associations. METHODS: This longitudinal study included 42,246 participants aged over 65 years from the Chinese Longitudinal Healthy Longevity Survey. The Mini-Mental State Examination and a self-reported scale were used to measure cognitive status and leisure activities, respectively. We examined the associations of cognitive function and leisure activities with mortality using Cox proportional hazards models. Causal mediation analysis was used to assess whether leisure activities mediated the association between cognitive function and mortality. RESULTS: Cognitive function and leisure activities were inversely associated with mortality. Leisure activities accounted for 28.3% (95% confidence interval [CI], 25.6 to 31.1) of the total effect (TE) of cognitive function and mortality. A higher mediated proportion (PM) was observed for physical leisure activities (PM, 20.1%; 95% CI, 18.0 to 22.3) than for social leisure activities (PM, 17.7%; 95% CI, 15.7 to 19.7). The mediating effect was higher among participants at younger ages (PM, 41.5%; 95% CI, 21.3 to 65.4), those with higher education levels (PM, 30.5%; 95% CI, 25.3 to 36.2), and residents of rural China (PM, 42.5%; 95% CI, 25.4 to 62.5). CONCLUSIONS: Cognitive function was associated with inverse mortality. Leisure activities significantly mediated this association. Participation in leisure activities at the early stages of mild cognitive impairment could reduce the risk of mortality, which has a major impact on interventional strategies for healthy aging.