• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.4
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• pp.973-983
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• 2015

To improve the control performance of the IPMSM, a novel nonlinear disturbance observer is proposed by using the T-S fuzzy model. A T-S fuzzy model is the combination of local linear models considered at each operating point. Usually the inverse model is easy to obtain in linear systems but not in nonlinear systems. To design a nonlinear disturbance observer, a nonlinear inverse model is obtained based on nonlinear inverse model which is the fuzzy combination of the local linear inverse models. The proposed DOB is used with a PDC controller which is one of the T-S fuzzy controller, and its performance improvement is shown from the simulation results.

• Structural Engineering and Mechanics
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• v.40 no.4
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• pp.471-488
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• 2011

The Ting Kau Bridge in Hong Kong is a cable-stayed bridge comprising two main spans and two side spans. The bridge deck is supported by three towers, an end pier and an abutment. Each of the three towers consists of a single reinforced concrete mast strengthened by transverse cables and struts. The bridge deck is supported by four inclined planes of cables emanating from anchorages at the tower tops. In view of the heavy traffic on the bridge, and threats from typhoons and earthquakes originated in areas nearby, the dynamic behaviour of long-span cable-supported bridges in the region is always an important consideration in their design. Baseline finite element models of various levels of sophistication have been built not only to match the bridge geometry and cable forces specified on the as-constructed drawings but also to be calibrated using the vibration measurement data captured by the Wind and Structural Health Monitoring System. This paper further describes the analysis of axle loading data, as well as the generation of random axle loads and simulation of vibrations of the bridge using the finite element models. Various factors affecting the vehicular loading on the bridge will also be examined.

• Wind and Structures
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• v.19 no.3
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• pp.249-270
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• 2014

Through comparing the mean wind profiles observed overland during the passages of four typhoons, and the gradient wind speeds calculated based on the sea level pressure data provided by a numerical model, the present paper discusses, (a) whether the gradient balance is a valid assumption to estimate the wind speed in the height range of 1250 m ~ 1750 m, which is defined as the upper-level mean wind speed, in a tropical cyclone over land, and (b) if the super-gradient feature is systematically observed below the height of 1500 m in the tropical cyclone wind field over land. It has been found that, (i) the gradient balance is a valid assumption to estimate the mean upper-level wind speed in tropical cyclones in the radial range from the radius to the maximum wind (RMW) to three times the RMW, (ii) the super-gradient flow dominates the wind field in the tropical cyclone boundary layer inside the RMW and is frequently observed in the radial range from the RMW to twice the RMW, (iii) the gradient wind speed calculated based on the post-landfall sea level pressure data underestimates the overall wind strength at an island site inside the RMW, and (iv) the unsynchronized decay of the pressure and wind fields in the tropical cyclone might be the reason for the underestimation.

• Journal of Distribution Science
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• v.15 no.4
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• pp.41-57
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• 2017

Purpose - With the growth of the duty free shop field and an increase in the executive interest in it, it becomes necessary to examine if PBZ (1988) SERVQUAL could be applied to duty free shop service reflecting on this increased interest and the importance of marketing strategy alternative managing multinational customers. Therefore, the present research focused on the comparison of Korean and Chinese consumers. We examined how service quality would affect relationship quality and customer loyalty. Research design, data, and methodology - Surveys were distributed to 235 Korean and 220 Chinese consumers who have visited a Korean duty free shop. We analyzed frequency analysis, mean difference analysis, and reliability analysis, exploratory factor analysis, confirmatory factor analysis, structural equation model analysis, and multi-group analysis. Results - First, perceived tangibles, responsiveness, empathy, assurance, price benefits, product diversity, and IT convenience of duty free shop service all appeared to be positive effect on customer satisfaction; at the same time, only tangibles, responsiveness, empathy, assurance, and price benefits positively affected customer trust. Secondly, customer satisfaction and trust that are the components of the relationship quality appeared to be positive effect on customer loyalty. Thirdly, customers' satisfaction was found to play a full mediating role effect among all of the service quality factors with customer loyalty; however, customer trust was found to have the mediating effects only with tangibles, empathy, assurance, and price benefits. Fourthly, we found a difference between how service quality influences relationship quality and how service quality influences customer loyalty as a function of different nationality. As a result, it appeared that price benefits and IT convenience affected customer satisfaction more among Koreans than among Chinese. Finally, it appeared that customer satisfaction and trust affected customer loyalty more among Chinese than among Koreans. Conclusions - The results of this study contribute to the theoretical knowledge, but also provide strategic alternatives to enhance differentiation, international competence of enterprises led by duty free shop and service quality improvement and customer loyalty of enterprises are drawn as a foundation for constructing international customer relationship in future global era.

• The Korean Journal of Pharmacology
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• v.26 no.1
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• pp.83-90
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• 1990

The effect of cimetidine on theophylline metabolism was examined in dogs. Single dose intravenous theophylline kinetic studies were performed in cross-over manner before and after one week intravenous cimetidine (30 mg/kg/day) treatment. Cimetidine decreased theophylline clearance by an average of 31% (p<0.05) and prolonged theophylline half-li fe by an average of 29% (p<0.01) compared to those in control peirods. However, steady-state volume of distribution and protein binding of theophylline were not changed significantly. Twenty-four hours urinary excretion of 3-methylxanthine, 1-methyluric acid and 1,3-dimethyluric acid, which are the major metabolites of theophylline, were all decreased after cimetidine treatment, whereas the excreted fractions of individual metabolites were unchanged by cimetidine. From the above data, it could be susggested that cimetidine decreases theophylline clearance and prolongs the half-life by non-specific inhibition of the demethylations and 8-hydroxylation pathways.

• The Korean Journal of Physiology and Pharmacology
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• v.18 no.3
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• pp.249-254
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• 2014

The purpose of this study is to characterize the effects of KHG26792 (3-(naphthalen-2-yl(propoxy)methyl)azetidine hydrochloride), a potential skin whitening agent, on melanin synthesis and identify the underlying mechanism of action. Our data showed that KHG26792 significantly reduced melanin synthesis in a dose-dependent manner. Additionally, KHG26792 downregulated microphthalmia-associated transcription factor (MITF) and tyrosinase, the rate-limiting enzyme in melanogenesis, although tyrosinase was not inhibited directly. KHG26792 activated extracellular signal-regulated kinase (ERK), whereas an ERK pathway inhibitor, PD98059, rescued KHG26792-induced hypopigmentation. These results suggest that KHG26792 decreases melanin production via ERK activation. Moreover, the hypopigmentary effects of KHG26792 were confirmed in a pigmented skin equivalent model using Cervi cornus Colla (deer antler glue), in which the color of the pigmented artificial skin became lighter after treatment with KHG26792. In summary, our findings suggest that KHG26792 is a novel skin whitening agent.

• Journal of Communications and Networks
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• v.10 no.3
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• pp.316-330
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• 2008

This paper proposes a novel method for transporting various types of user traffic effectively over the next generation network called integrated services digital network 3 (ISDN3) (or quantum network) using quantum packets. Basically, a quantum packet comprises one or more 53-byte quanta as generated by a "quantumization" process. While connection-oriented traffic is supported by fixed-size quantum packets each with one quantum to emulate circuit switching, connectionless traffic (e.g., IP packets and active packets) is carried by variable-size quantum packets with multiple quanta to support store-and-forward switching/routing. Our aim is to provide frame-like or datagram-like services while enabling cell-based multiplexing. The quantum packet method also establishes a flexible and extensible framework that caters for future packetization needs while maintaining backward compatibility with ATM. In this paper, we discuss the design of the quantum packet method, including its format, the "quantumization" process, and support for different types of user traffic. We also present an analytical model to evaluate the consumption of network resources (or network costs) when quantum packets are employed to transfer loss-sensitive data using three different approaches: cut-through, store-and-forward and ideal. Close form mathematical expressions are obtained for some situations. In particular, in terms of network cost, we discover two interesting equivalence phenomena for the cut-through and store-and-forward approaches under certain conditions and assumptions. Furthermore, analytical and simulation results are presented to study the system behavior. Our analysis provides valuable insights into the. design of the ISDN3/quantum network.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.11
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• pp.4563-4570
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• 2015

Background: Smoking is a learnt behavior during adolescence and understanding the factor/s associated with smoking will assist in identifying suitable measures in combating the rising prevalence of smoking among adolescents. This research aimed to identify the factor/s associated with smoking among form four students in Kota Tinggi, Johor. Multistage sampling was used to select a representative sample of students in 2008 and data were collected using a self-administered validated questionnaire. This study revealed that the overall smoking prevalence was 19.0% with a significantly higher proportion of male smokers (35.8%) as compared to females (3.15%). Adolescents who were male (aOR 6.6, 95%CI 2.61-16.4), those who had peer/s who smoked (aOR 4.03, 95% CI 1.31-12.4), and those who studied in rural areas and Felda Settlements ( aOR 4.59, 95 CI 1.11-18.0; aOR 9.42, 95%CI 3.91-29.1) were more likely to smoke in the past one week. On the other hand, adolescents with better knowledge on the hazards of smoking and negative attitudes towards smoking were less likely to smoke (aOR 0.51, 95%CI 0.37-0.72; aOR 0.67, 95%CI 0.46-0.99). Future promotional and interventional programmes on smoking should be considered and the above identified risk factors integrated to reduce smoking prevalence among students of school-going ages in Kota Tinggi. Johor.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.22 no.4
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• pp.489-498
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• 1998

Among the heat/mass exchange units composing an absorption system, the absorber, where the refrigerant vapor is absorbed into the liquid solution is the one least understood. In the present study, the effects of non-absorbable gas on the absorption process of aqueous lithium bromide solution falling film inside a vertical tube were experimentally investigated. In the range of film Reynolds number of 30 ~ 195, heat and mass transfer characteristics were investigated as a function of non-absorbable gas volumetric concentration, 0.2 ~ 20%. An increase of non-absorbable gas volumetric concentration degraded the mass transfer rate dramatically in the absorption process. The reduction of mass transfer rate was significant for the addition of small amount of non-absorbable gas to the pure vapor. At film Reynolds number of 130, an increase of non-absorbable gas concentration from 0.2 to 6.0% resulted in the decrease of mass transfer rate by 36% and 20% of non-absorbable gas by 59%. However the decrease of film Nusselt number with the increase of volumetric concentration of non absorbable gas was relatively smaller than the decrease of Sherwood number. Critical film Reynolds number was identified to exist for the maximum heat and mass transfer regardless of the volumetric concentration of non-absorbable gases.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.18
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• pp.7995-8001
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• 2014

Interferon-gamma (IFN-${\gamma}$) has been used to treat various malignant tumors. However, the molecular mechanisms underlying the direct anti-proliferative activity of IFN-${\gamma}$ are poorly understood. In the present study, we examined the in vitro antitumor activity of IFN-${\gamma}$ on two human non-small-cell lung carcinoma (NSCLC) cell lines, H322M and H226. Our findings indicated that IFN-${\gamma}$ treatment caused a time-dependent reduction in cell viability and induced apoptosis through a FADD-mediated caspase-8/tBid/mitochondria-dependent pathway in both cell lines. Notably, we also postulated that IFN-${\gamma}$ increased indoleamine 2,3-dioxygenase (IDO) expression and enzymatic activity in H322M and H226 cells. In addition, inhibition of IDO activity by the IDO inhibitor 1-MT or tryptophan significantly reduced IFN-${\gamma}$-induced apoptosis and death receptor 5 (DR5) expression, which suggests that IDO enzymatic activity plays an important role in the anti-NSCLC cancer effect of IFN-${\gamma}$. These results provide new mechanistic insights into interferon-${\gamma}$ antitumor activity and further support IFN-${\gamma}$ as a potential therapeutic adjuvant for the treatment of NCSLC.