Time filter

Source Type

Chen Y.-L.,National Central University | Cheng L.-C.,Soochow University of Taiwan
Decision Support Systems | Year: 2010

The group ranking problem is used to construct coherent aggregate results from preference data provided by decision makers. Although there have been different input formats used to represent user preferences, they share a common weakness, that the input mode is static. In other words, users must provide all the preference data at one time. To overcome this weakness, we propose a framework which allows users to provide partial and/or incomplete preference data at multiple times. Since this is a complicated issue, we specifically focus on a particular aspect as a first attempt at this framework. Accordingly, we reexamine a variant of the group ranking problem, the maximum consensus mining problem, which will give the longest ranking lists of alternatives that agree with the majority and disagree only with the minority, under the dynamic input mode assumption. An algorithm is developed to determine the maximum consensus sequences from the users' partial ranking data. Finally, extensive experiments are carried out using synthetic data sets. The results indicate that the proposed method is computationally efficient, and can effectively identify consensus among all users. © 2009 Elsevier B.V. All rights reserved.

Lee C.-M.,Soochow University of Taiwan | Hsu S.-L.,National Chiayi University
International Journal of Production Economics | Year: 2011

Advertising is very important for the newsboy problem because the shelf-life of the newsboy product is short and advertising may increase sales to avoid overstocking. In this paper, models to study the effect of advertising are developed for the distribution-free newsboy problem where only the mean and variance of the demand are known. As in Khouja and Robbins (2003), it is assumed that the mean demand is an increasing and concave function of advertising expenditure. Three cases are considered: (1) demand has constant variance, (2) demand has constant coefficient of variation, and (3) demand has an increasing coefficient of variation. This paper provides closed-form solutions or steps to solve the problem. Numerical results of the model are also compared with those from other papers. The effects of model parameters on optimal expenditure on advertising, optimal order quantity, and the lower bound on expected profit are derived or discussed. © 2010 Elsevier B.V. All rights reserved.

Leong M.-I.,Instituto para os Assuntos Civicos e Municipais IACM | Fuh M.-R.,Soochow University of Taiwan | Huang S.-D.,National Tsing Hua University
Journal of Chromatography A | Year: 2014

Dispersive liquid-liquid microextraction (DLLME) and other dispersion liquid-phase microextraction (LPME) methods have been developed since the first DLLME method was reported in 2006. DLLME is simple, rapid, and affords high enrichment factor, this is due to the large contact surface area of the extraction solvent. DLLME is a method suitable for the extraction in many different water samples, but it requires using chlorinated solvents. In recent years, interest in DLLME or dispersion LPME has been focused on the use of low-toxicity solvents and more conveniently practical procedures. This review examines some of the most interesting developments in the past few years. In the first section, DLLME methods are separated in two categories: DLLME with low-density extraction solvent and DLLME with high-density extraction solvent. Besides these methods, many novel special devices for collecting low-density extraction solvent are also mentioned. In addition, various dispersion techniques with LPME, including manual shaking, air-assisted LPME (aspirating and injecting the extraction mixture by syringe), ultrasound-assisted emulsification, vortex-assisted emulsification, surfactant-assisted emulsification, and microwave-assisted emulsification are described. Besides the above methods, combinations of DLLME with other extraction techniques (solid-phase extraction, stir bar sorptive extraction, molecularly imprinted matrix solid-phase dispersion and supercritical fluid extraction) are introduced. The combination of nanotechnique with DLLME is also introduced. Furthermore, this review illustrates the application of DLLME or dispersion LPME methods to separate and preconcentrate various organic analytes, inorganic analytes, and samples. © 2014 Elsevier B.V.

The dynamic second-order hyperpolarizability from the third-harmonic generation experiment, 〈γ〉 (-3ωωωω), of 59 solution-phase organic molecules has been theoretically calculated and compared with available experimental data. The DFT/6-311+G(2d,p)//(CAM-)B3LYP/6-31G(2df,p) level of theory with the polarizable continuum model was employed to evaluate the static second-order hyperpolarizability. The theoretical static values were then corrected to dynamic estimates of 〈γ〉 (-3ωωωω) by employing a two-level approximation (Chen et al. in J Chem Phys 101(7):5860-5864, 1994). Calculated results showed that for the property of interest, the range-separated hybrids provided more accurate and consistent estimate than the global hybrids and the CAMB3LYP optimized geometry delivered more accurate estimate than the B3LYP optimized geometry. © Springer-Verlag Berlin Heidelberg 2013.

Lu S.-I.,Soochow University of Taiwan
Chemical Physics Letters | Year: 2013

Density functional theory has been used to calculate the μ·β(-2ν;ν,ν,0) on a series of solution-phase hydrazones. Using the experimental and MP2(Full) calculated data as references, the qualitative trend of the Hartree-Fock, M06-HF and range-separated hybrids have been examined. Our results propose methods with long-range corrections, and without short-range exact exchange, are capable of qualitatively predicting the nonlinear optical responses of the hydrazones when reliable geometries have been provided. The same conclusion can also be applied to solution-phase push-pull phenylpolyenes. © 2013 Elsevier B.V. All rights reserved.

Kuo Y.-C.,Soochow University of Taiwan
Computer Networks | Year: 2010

The asynchronous PS (Power-Saving) unicast protocol was designed for two PS wireless hosts to transmit the unicast message in the ad hoc network even their clocks are asynchronous. However, as regard to transmit a multicast message among more than two PS hosts, the protocol could not guarantee that all PS hosts can wake up at the same time. Some PS hosts may be in the PS mode when the multicast message is transmitted. Thus, the multicast message should be retransmitted again and again until all PS hosts receive the message. It will increase the energy consumption and the usage of the bandwidth. In this paper, we propose quorum-based PS multicast protocols for PS hosts to transmit multicast messages in the asynchronous ad hoc network. In those protocols, PS hosts use quorums to indicate their wakeup patterns. We introduce the rotation m-closure property to guarantee that m different quorums have the intersection even quorums are rotated due to asynchronous clocks. Thus, m PS hosts adopting m quorums satisfying the rotation m-closure property could wake up simultaneously and receive the multicast message even their clocks are asynchronous. We propose two quorum systems named the uniform k-arbiter and the CRT (Chinese Remainder Theorem) quorum system, which satisfy the rotation m-closure property. As shown in our analysis results, our quorum-based PS multicast protocols adopting those quorum systems can save more energy to transmit multicast messages. © 2010 Elsevier B.V. All rights reserved.

Lin S.-L.,Soochow University of Taiwan | Fuh M.-R.,Soochow University of Taiwan
Journal of Chromatography A | Year: 2010

Orthogonal array design (OAD) was utilized for the first time to optimize the experimental conditions of ultrasound-assisted emulsification-microextraction (USAEME) for determining chlorinated phenoxyacetic acids (CPAs) in river water samples. The use of ultrasound facilitates the mass transfer of CPAs from an aqueous phase into a water-immiscible organic extraction solvent (dichloromethane, DCM) without adding dispersive solvent to form numerous microdroplets. The water-immiscible extractant was collected by centrifugation, dried under low pressure, reconstituted in methanol-water mixture (1:1), and injected into a HPLC system for the determination of CPAs. The linear range was 2-1000ngmL -1 (2, 5, 10, 50, 200, 500 and 1000ngmL -1) for each analyte and the relative standard deviations of CPAs among the seven different concentrations were in the range of 1.5-17.0% (n=3). The detection limits (signal-to-noise ratio of 3) of CPAs ranged from 0.67 to 1.50ngmL -1. The ranges of intra-day precision (n=3) for CPAs at the levels of 5 and 200ngmL -1 were 3.6-11.9% and 5.3-9.5%, respectively. The range of inter-day precision (n=3) at 5 and 200ngmL -1 were 1.4-7.7% and 8.5-12.2%, respectively. The applicability of USAEME for environmental analysis was demonstrated by determining CPAs in river water. The recoveries of CPAs from five-spiked river water samples at 10 and 200ngmL -1 were 96.3-112.5% and 94.8-109.4%, respectively. The maximum contaminant level (MCL) of 2,4-D in drinking water and the tolerance of residues in food for p-CPA are 70 and 200μgL -1, respectively, according to the US EPA regulations. These contaminant levels fall in the linear range investigated in this study. In addition, this USAEME method provided detection limits lower than their contaminant levels, which made USAEME an effective sample preparation method for determining organic environmental contaminants, such as CPAs, in river water samples with little consumption of organic solvent. © 2010 Elsevier B.V.

Chu H.-C.,Soochow University of Taiwan
Educational Technology and Society | Year: 2013

Owing to the advancement of mobile and wireless communication technologies, an increasing number of mobile learning studies have been conducted in recent years. In a mobile learning environment, students are able to learn indoors and outdoors with access to online resources at any time. However, whether or not new learning scenarios that combine both real-world contexts and digital-world resources are beneficial to the students has been questioned. Moreover, it is also interesting to probe whether the existing e-learning strategies are effective when situated in those mobile learning scenarios. In this study, an in-field activity on an indigenous culture course of an elementary school with a formative assessment-based learning strategy was conducted to investigate the possible negative effects of mobile learning by analyzing the students' cognitive load and learning achievement. It is interesting to find that, without proper treatment, the performance of students using those existing online learning strategies, known to be "effective," might be disappointing or may even negatively affect the students' learning achievements. Furthermore, the negative effects could be due to the heavy cognitive load caused by an improper learning design. Such findings offer good references for those who intend to design and conduct mobile learning activities. © International Forum of Educational Technology & Society (IFETS).

The International Financial Reporting Standards (IFRS) No. 2 has been the worldwide accounting principle for the reduction of inventory to market allowance since January 1, 2005. Using make-to-stock manufacturing strategies and inventory accounting for only approximately 14% of the total costs, integrated device manufacturers have found maintaining robust records for financial statements increasingly difficult. For example, one company in the case study conducted in this study must write-down losses of 2- 100% of the total inventory costs for products with inventory ages of 18 months-3 years. However, the average cycle time for producing flash memory is approximately 3 months. In other words, when the system variation and safety stock policy are considered, the company must write-down the reduction of inventory to market allowance for most of work-in-process inventory. However, little research has been done to addressing the practical management of operations according to inventory aging processes. This study develops a polynomial-time-based model to obtain significant features, including inventory ages, accounting principles, and product structures (bill of material), for the accurate prediction of inventory write-downs to reduce the impact of the carrying value fluctuation of inventory. An empirical study was conducted on a Taiwanese semiconductor manufacturer. The results show that predicting 3-month inventory write-downs of a complete flash memory production line comprising approximately 8500 product types can be conducted in less than 10 s, with the mean absolute percentage error (MAPE) less than 3.5%. Discussions regarding the sensitivity analysis and cost tornado diagrams suggest the priority of affecting factors. The results show the viability of implementing the proposed model to predict inventory write-downs in the semiconductor manufacturing industry. © 2011 Elsevier Ltd. All rights reserved.

Lu S.-I.,Soochow University of Taiwan
Journal of Computational Chemistry | Year: 2011

Various hybrid functionals (B3LYP, B97-2, PBE0, BMK, BH&HLYP, CAM-B3LYP, and LC-ÏPBE) implemented in density functional theory were applied to give estimate of static first hyperpolarizabilty (β 0) of (E)-benzaldehyde phenylhydrazone designated as (E)-BPH. Against those of MP2 computations as a function of the underlying density functional, good agreement was obtained with the BH&HLYP and CAM-B3LYP functionals. The LC-ÏPBE functional and the B3LYP, PBE0, B97-2, and BMK functionals underestimated and overestimated β 0, respectively. The basis set effect on the calculated β 0 was also investigated. It turned out that the 6-311+G(2d,p) basis set provided excellent converged value of β 0. On the basis of the calculated results, we investigated the substituent effect on β 0 of donor-acceptor (D-A) substituted (E)-BPH systematically by using the BH&HLYP and CAM-B3LYP computations with the 6-311+G(2d,p) basis set. We proposed a Zwitterion structure to explain the calculated trend in the substituent effect and the enhanced hyperpolarizability of type II compounds (A-(E)-BPH-D) than type I compounds (D-(E)-BPH-A). Natural bonding orbital analysis carried out at BH&HLYP/6-311+G(2d,p)//B3LYP/6- 31G(2df,p) level of theory substantiated the claim. © 2010 Wiley Periodicals, Inc.

Loading Soochow University of Taiwan collaborators
Loading Soochow University of Taiwan collaborators