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Jaehun Park(박재훈),Sungmook Lim(임성묵),Hyerim Bae(배혜림) 대한산업공학회 2014 대한산업공학회지 Vol.40 No.6
Stepwise efficiency improvement in data envelopment analysis (DEA)-based benchmarking is a realistic and effective method by which inefficient decision making units (DMUs) can choose benchmarks in a stepwise manner and, thereby, effect gradual performance improvement. Most of the previous research relevant to stepwise efficiency improvement has focused primarily on how to stratify DMUs into multiple layers and how to select immediate benchmark targets in leading levels for lagging-level DMUs. It can be said that the sequence of benchmark targets was constructed in a myopic way, which can limit its effectiveness. To address this issue, this paper proposes an optimization approach to the construction of a sequence of benchmarks in DEA-based benchmarking, wherein two optimization criteria are employed : similarity of input-output use patterns, and proximity of input-output use levels between DMUs. To illustrate the proposed method, we applied it to the benchmarking of 23 national universities in South Korea.
Park Cheol,Cha Hee-Jae,Kim Da Hye,Kwon Chan-Young,Park Shin-Hyung,Hong Su Hyun,Bang EunJin,Cheong Jaehun,Kim Gi-Young,Choi Yung Hyun 한국미생물·생명공학회 2023 Journal of microbiology and biotechnology Vol.33 No.5
Fisetin is a bioactive flavonol molecule and has been shown to have antioxidant potential, but its efficacy has not been fully validated. The aim of the present study was to investigate the protective efficacy of fisetin on C2C12 murine myoblastjdusts under hydrogen peroxide (H2O2)-induced oxidative damage. The results revealed that fisetin significantly weakened H2O2-induced cell viability inhibition and DNA damage while blocking reactive oxygen species (ROS) generation. Fisetin also significantly alleviated cell cycle arrest by H2O2 treatment through by reversing the upregulation of p21WAF1/CIP1 expression and the downregulation of cyclin A and B levels. In addition, fisetin significantly blocked apoptosis induced by H2O2 through increasing the Bcl-2/Bax ratio and attenuating mitochondrial damage, which was accompanied by inactivation of caspase-3 and suppression of poly(ADP-ribose) polymerase cleavage. Furthermore, fisetin-induced nuclear translocation and phosphorylation of Nrf2 were related to the increased expression and activation of heme oxygenase-1 (HO-1) in H2O2- stimulated C2C12 myoblasts. However, the protective efficacy of fisetin on H2O2-mediated cytotoxicity, including cell cycle arrest, apoptosis and mitochondrial dysfunction, were greatly offset when HO-1 activity was artificially inhibited. Therefore, our results indicate that fisetin as an Nrf2 activator effectively abrogated oxidative stress-mediated damage in C2C12 myoblasts.
PAL-XFEL soft X-ray scientific instruments and X-ray optics: First commissioning results
Park, Sang Han,Kim, Minseok,Min, Changi-Ki,Eom, Intae,Nam, Inhyuk,Lee, Heung-Soo,Kang, Heung-Sik,Kim, Hyeong-Do,Jang, Ho Young,Kim, Seonghan,Hwang, Sun-min,Park, Gi-Soo,Park, Jaehun,Koo, Tae-Yeong,Kwo American Institute of Physics 2018 Review of scientific instruments Vol.89 No.5
Park, Jaeheung,Lee, Taegon,Park, Jaehun,Lim, Manho American Chemical Society 2013 The journal of physical chemistry. B, Condensed ma Vol.117 No.10
<P>Femtosecond vibrational spectroscopy was used to investigate the photoexcitation dynamics of NO-bound ferric myoglobin (Mb<SUP>III</SUP>NO) in D<SUB>2</SUB>O solution at 294 K after excitation with a 575 nm pulse. The stretching mode of NO in Mb<SUP>III</SUP>NO consists of a major band at 1922 cm<SUP>–1</SUP> (97.7%) and a minor band at 1902 cm<SUP>–1</SUP> (2.3%), suggesting that Mb<SUP>III</SUP>NO in room temperature solution has two conformational substates. The time-resolved spectra show small but significant new absorption features at the lower-energy side of the main band (1920–1800 cm<SUP>–1</SUP>). One new absorption feature in the region of 1920–1880 cm<SUP>–1</SUP> exhibits the <SUP>15</SUP>NO isotope shift (37 cm<SUP>–1</SUP>) the same as that of the NO band in the ground electronic state of Mb<SUP>III</SUP>NO. This absorption shifts toward higher energy and narrows with a time constant of 2.4 ps, indicating that it evolves with rapid electronic and thermal relaxation of the photoexcited Mb<SUP>III</SUP>NO without photodeligation of the NO from the heme. Absorption features assigned to proteins undergoing thermal relaxation without NO deligation add up to 14 ± 1% of the total bleach, implying that the photolysis quantum yield of Mb<SUP>III</SUP>NO with a Q-band excitation is ≤0.86 ± 0.01. The remaining absorption bands peaked near 1867, 1845, and 1815 cm<SUP>–1</SUP>, each showing the <SUP>15</SUP>NO isotope shift the same as that of the free NO radical (33 cm<SUP>–1</SUP>), were assigned to the vibrational band of the photodeligated NO, the NO band of Mb<SUP>III</SUP>NO in an intermediate electronic state with low-spin Fe(III)–NO(radical) character (denoted as the R state), and the NO band of the vibrationally excited NO in the R state, respectively. A kinetics model successfully reproducing the time-dependent intensity changes of the transient bands suggests that every rebound NO forms the R state that eventually relaxes into the ground electronic state nonexponentially. Most of the photodissociated NO undergoes fast geminate recombination (GR), and the rebinding kinetics depends on the conformation of the protein. GR of NO to Mb<SUP>III</SUP> in the major conformation shows highly nonexponential kinetics described by a stretched exponential function, exp(−(<I>t</I>/290 ps)<SUP>0.44</SUP>. The NO rebinding to Mb<SUP>III</SUP> in the minor conformation is exponential, exp(−<I>t</I>/1.8 ns), suggesting that the distal histidine, the interaction of which dictates the conformation of Mb<SUP>III</SUP>NO, participates in mediating the binding of NO to Mb<SUP>III</SUP>. In Mb<SUP>III</SUP>NO, the elusive low-spin Fe(III)–NO(radical) state, proposed in electronic structure calculations, indeed exists at >12 kJ/mol above the ground state and takes part in the bond formation of Fe(III)–NO, suggesting that it plays a significant role in the function of NO-bound ferric protein. Time-resolved vibrational spectra with high sensitivity reveal rich photophysical and photochemical processes of photoexcited Mb<SUP>III</SUP>NO.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/jpcbfk/2013/jpcbfk.2013.117.issue-10/jp400055d/production/images/medium/jp-2013-00055d_0013.gif'></P>
Multi-Criteria ABC Inventory Classification Using the Cross-Efficiency Method in DEA
Jaehun Park(박재훈),Hyerim Bae(배혜림),Sungmook Lim(임성묵) 대한산업공학회 2011 대한산업공학회지 Vol.37 No.4
Multi-criteria ABC inventory classification, which aims to classify inventory items by considering more than one criterion, is one of the most widely employed techniques for inventory control. The weighted linear optimization (WLO) model proposed by Ramanathan (2006) solves the problem of multi-criteria ABC inventory classification by generating a set of criterion weights for each inventory item and assigning a normalized score to the item for ABC analysis. However, the WLO model has some limitations. First, many inventory items can share the same optimal score, which can hinder a precise classification of inventory items. Second, the model allows too much flexibility in weighting multiple criteria; each item is allowed to choose its own weights so that it can maximize its score. As a result, if an item dominates the others in terms of a certain criterion, it may be classified into a higher class regardless of other criteria by assigning an overwhelming weight to the criterion. Consequently, an item with a high value in an unimportant criterion and low values in others may be inappropriately classified as class A, leading to an inaccurate classification of inventory items. To overcome these shortcomings, we extend the WLO model by using the cross-efficiency method in data envelopment analysis. We claim that the proposed model can provide a more reasonable and accurate classification of inventory items by mitigating the adverse effect of flexibility in the choice of weights and yielding a unique ordering of inventory items.
박재훈(Jaehun Park),김용정(Yong-Jeong Kim) 한국무역연구원 2020 무역연구 Vol.16 No.1
Purpose- The aim of this study is to suggest the diversification model for the growth of trucking companies through actual case research which have previously proceeded the diversification under the unique situation of Korea. Design/methodology/approach- This study delves into two real cases of trucking companies and tracking their progress relative to their business diversification using unique corporate growth strategies. The case approach qualitative research methodology was used including site visits, and in-depth interviews with the key informants. Findings- Results of the case study reveal that, the trucking companies have demonstrated strength in promoting business diversification specializing in the function of transportation as its core competence and this is where the growth strategy of the company is focused on. It was determined that business diversification progressed towards route cargo transportation, then parcel delivery service and eventually did international express delivery. Research implications or Originality- The case study presents evidence of a business model showing the use of an effective growth strategy of a trucking company through diversification. This study has suggested the orientation of logistics diversification of trucking companies corresponding with the reality based on cases of diversification, and it has the meaning in which it provides the foundation to growth strategy of trucking companies in future.