Logistic regression in sealed-bid auctions with multiple rounds: Application in Korean court auction

This paper proposes a forecasting method for court auction information system using logistic regression model with heterogeneity across the multiple round. The goal is to predict whether an individual auction item in a certain round will be sold or not. A simple linear regression and the least angle regression (LARS) containing random effect terms were used to select meaningful variables for our logit model. The link function of the proposed logit model is represented by two bundles of parameters. The former part consists of the parameters whose values do not change over rounds. The latter part has parameters whose values interact with rounds. The observed data corresponding to an appraiser price as well as an intercept term reflecting local characteristics are used without any change. Data that corresponds to all the other parameters is not directly used, but transformed based on similarities between the original item and the surrounding auction items being recommended by the court auction experts. We tested the Bayesian logistic regression by establishing different priors: Dunson’s prior, Gelman’s prior and Ansari’s prior. Dunson’s prior was found to perform the best. Little significant difference was found between the results of the other two priors. These findings indicate that logistic regression taking the heterogeneity of multi-round into account performs better than a one-layered neural network over all time periods.     

Dynamic traffic prediction for insufficient data roadways via automatic control theories

This study aims to propose an algorithm for traffic estimation, particularly for urban roadway sections with insufficient data sources. Establishing an advanced traffic management system (ATMS) heavily depends on obtaining complete data. In this regard, traffic detectors play an important role in data acquisition. However, installing traffic detectors extensively over a metropolitan area can be rather expensive. As such, in most cities around the world, vehicle detectors for traffic data collection are relatively insufficient to meet requirements. In light of this, the current research therefore proposes a feasible algorithm of dynamic section flow prediction based on the automatic control theory and observer design for roadway sections with insufficient data sources. According to the numerical evaluation, the method is found to be satisfactory and acceptable in practice.     

T–S fuzzy model-based tracking control of a one-dimensional manipulator actuated by pneumatic artificial muscles

Pneumatic artificial muscle (PAM) has highly nonlinear and time-varying behavior due to gas compression and nonlinear elasticity of the bladder containers. Hence, it is difficult to achieve excellent tracking performance when using classical control methods. This study proposes a Takagi–Sugeno (T–S) fuzzy model-based control for improving control performance. The proposed approach decomposes the model of a nonlinear system into a set of linear subsystems. This allows, the T–S fuzzy model-based controller to use simple linear control techniques providing a systematic framework for the design of a state feedback controller. Stability analysis is carried out using Lyapunov direct method. The powerful LMI Toolbox in MATLAB is employed to solve linear matrix inequalities (LMIs) to obtain the controller gains. Experimental results verified that the proposed controller can achieve excellent tracking performance under different disturbances.     

基于正则表示的SQL注入过滤模块设计

研究SQL注入攻击行为及语法特征,采用正则表达式对攻击特征进行描述,在此基础上设计Web服务端SQL注入攻击过滤模块,使Http请求被提交至系统模块处理前实现注入攻击检查。测试结果表明,与单纯基于关键字的过滤相比,基于正则表示的过滤具有更高的识别率和较低的误报率,加载了过滤模块的Web服务器能较好地拦截多种SQL注入攻击,并且服务延迟较小。     

Consideration factors and adoption of type,tabulation and framework for creating e-portfolios

The purpose of this research is to analyze the content of e-portfolios created by students in order to understand their tabulation and ways of displaying content. The analytic result shows that the number of outcome portfolios created by students is more than that of process portfolios. The five types of e-portfolio tabulation, in order of those most commonly created by students, are combination-based, content item-based, work-based, course unit-based, and time-based. The combination-based type incorporates the advantages of other tabulation types, while the content item-based and work-based types are better for clearly classifying data and step-by-step organization of it. Future research may further explore factors related to students’ decision of tabulation type, the difficulties they face in the process, and their mentality as they adopt a portfolio type.     

An efficient tabu search algorithm to the cell formation problem with alternative routings and machine reliability considerations

Cell formation is the first step in the design of cellular manufacturing systems. In this study, an efficient tabu search algorithm based on a similarity coefficient is proposed to solve the cell formation problem with alternative process routings and machine reliability considerations. In the proposed algorithm, good initial solutions are first generated and later on improved by a tabu search algorithm combining the mutation operator and an effective neighborhood solution searching mechanism. Computational experiences from test problems show that the proposed approach is extremely effective and efficient. When compared with the mathematical programming approach which took three hours to solve problems, the proposed algorithm is able to produce optimal solutions in less than 2 s.     

Exploring the value of purchasing online game items

The aims of this paper are to: (1) modify the theory of consumption values in order to investigate online game users’ perceived value of purchasable game items, and (2) develop a new construct – the “integrated value of purchasing game items” – based on the modified theory of consumption values. We found that the enjoyment, character competency, visual authority, and monetary values are appropriate for describing how online game users perceive the value of game items. Utilizing second order analysis, the “integrated value of purchasing game items” was developed. To show the validity of the new construct, we developed a research model and tested it using the results of 327 valid questionnaires. Results revealed that the new construct is statistically significant in affecting users’ intention to purchase game items.     

On global solutions to fractional functional differential equations with infinite delay in Fréchet spaces

In this paper, we investigate global uniqueness results for fractional functional differential equations with infinite delay in Fréchet spaces. We shall rely on a nonlinear alternative of Leray-Schauder type in Fréchet spaces due to Frigon and Granas. The results are obtained by using the α-resolvent family (S_α(t))_t≥0 on a complex Banach space X combined with the above-mentioned fixed point theorem. As an application, a controllability result with one parameter is also provided to illustrate the theory.     

Multiwalled carbon nanotubes grafted chitosan nanobiocomposite: A prosperous functional nanomaterials for glucose biosensor application

Multiwalled carbon nanotubes (MWNTs) grafted chitosan (CS) nanowire (NW) was prepared by phase separation method. Glucose oxidase (GOx) was sequentially immobilized into MWNT-CS-NW to obtain MWNT-CS-NW/GOx biosensor. Field emission scanning electron microscopy (FESEM) images of MWNT-CS-NW/GOx reveals the existence of MWNT and CS. Cyclic voltammetry and amperometry were used to evaluate the electrochemical determination of glucose. The MWNT-CS-NW/GOx biosensor shows an excellent performance for glucose at +0.34 V with a high sensitivity (5.03 μA/mM) and lower response time (3 s) in a wide concentration range of 1-10 mM (correlation coefficient of 0.9988). In addition, MWNT-CS-NW/GOx biosensor possesses better reproducibility, storage stability and there is negligible interference from other electroactive components.     

Micro-piezoelectric immunoassay chip for simultaneous detection of Hepatitis B virus and α-fetoprotein

In this paper, a piezoelectric diaphragm-based immunoassay chip was developed to simultaneously detect anti-Hepatitis B virus (HBV) and anti-alpha-fetoprotein (AFP). The chip was fabricated by micro-machining technology and consists of eight individual circular sensors with a diameter of 800 μm. Hepatitis B surface antigen (HBsAg), Hepatitis C core antigen (HBcAg) and AFP as the probe molecules were immobilized on different sensing spots on the chip. A solution containing anti-HBsAg and anti-AFP was applied into the reaction chambers in all sensors of the chip, and significant frequency shifts were only observed in the sensors with HBsAg and AFP for immunoassay detection. The fluorescence image further confirmed the successful detection of anti-HBsAg and anti-AFP. The total assay time was less than 2 h. The frequency shift-based calibration curves show a detection limit of 0.1 ng/ml and a dynamic detection range of 0.1-10,000 ng/ml for both anti-HBsAg and anti-AFP, respectively, thus demonstrating that the developed piezoelectric immunoassay chip has potential applications for rapid, specific, sensitive, and multiple detections of HBV.