• Journal of the Korean Society for information Management
• /
• v.33 no.1
• /
• pp.317-336
• /
• 2016

Nowadays users spend more time and effort to find what they want because of information overload. To solve the problem, scientific article recommendation system analyse users' needs and recommend them proper articles. However, most of the scientific article recommendation systems neglected the core part, user profile. Therefore, in this paper, instead of mean which applied in user profile in previous studies, New TPIPF (Topic Proportion-Inverse Paper Frequency) was applied to scientific article recommendation system. Moreover, the accuracy of two scientific article recommendation systems with above different methods was compared with experiments of public dataset from online reference manager, CiteULike. As a result, the proposed scientific article recommendation system with TPIPF was proven to be better.

• The Korean Journal of Applied Statistics
• /
• v.25 no.5
• /
• pp.847-857
• /
• 2012

This article is concerned with choice-based conjoint analysis versus rating-based and ranking-based conjoint analysis. Choice-based conjoint analysis has a definite advantage in that the respondent's task of choosing the most preferred profile from several competing profiles adequately mimics consumer marketplace behavior. It is crucial to design the choice sets appropriate for the choice-based conjoint. Thus, this article suggests a new method to design the choice sets that are well-balanced. It augments the balanced incomplete block design and then obtains the dual design of the result to accommodate various numbers of profiles. In consequence, the choice sets designed by the new method have the desirable characteristics that each profile is presented to the same number of respondents, and pairs of any two distinct profiles occur together in the same number of choice sets. The balancing of the design increases the efficiency of the conjoint analysis. In addition, the pair-comparison scheme can improve the quality of data through the identification of contradictory responses.

• International Journal of Railway
• /
• v.6 no.4
• /
• pp.148-154
• /
• 2013

This article has tried to review the maximum contact stresses in the contact area of the wheel and rail as a result of lateral movement of the wheel on rail by taking advantage from Hertz theory. Since wheel movement on rail is accompanied by lateral movement due to wheel profile conisity, so the contact point of wheel and rail is not constant and the contact stresses are therefore changeable in every single moment. Since the shape of rail profile and rail inclination, wheel diameter and the mechanical properties of the wheel and rail are effective on the stresses of contact area, these parameters have been studied by applying Hertz theory. This article aims to calculate the contact stresses in different parts on the wheel surface by using Hertz theory.

• The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
• /
• v.3 no.2
• /
• pp.79-83
• /
• 1992

The demand for small and low-profile antennas has become quite strong, especially in mobile communications. This article presents an brief introduction to the fundsmental characteristics, design, and measurement of typical small antennas and low-profile antennas.

• Transactions on Electrical and Electronic Materials
• /
• v.17 no.5
• /
• pp.270-274
• /
• 2016

This article investigates the use of the Gaussian-channel doping profile for the control of the short-channel effects in the double-gate MOSFET whereby a two-dimensional (2D) quantum simulation was used. The simulations were completed through a self-consistent solving of the 2D Poisson equation and the Schrodinger equation within the non-equilibrium Green’s function (NEGF) formalism. The impacts of the p-type-channel Gaussian-doping profile parameters such as the peak doping concentration and the straggle parameter were studied in terms of the drain current, on-current, off-current, sub-threshold swing (SS), and drain-induced barrier lowering (DIBL). The simulation results show that the short-channel effects were improved in correspondence with incremental changes of the straggle parameter and the peak doping concentration.

• Journal of Magnetics
• /
• v.21 no.3
• /
• pp.468-475
• /
• 2016

In this article, entropy generation on MHD Williamson nanofluid over a porous shrinking sheet has been analyzed. Nonlinear thermal radiation and chemical reaction effects are also taken into account with the help of energy and concentration equation. The fluid is electrically conducting by an external applied magnetic field while the induced magnetic field is assumed to be negligible due to small magnetic Reynolds number. The governing equations are first converted into the dimensionless expression with the help of similarity transformation variables. The solution of the highly nonlinear coupled ordinary differential equation has been obtained with the combination of Successive linearization method (SLM) and Chebyshev spectral collocation method. Influence of all the emerging parameters on entropy profile, temperature profile and concentration profile are plotted and discussed. Nusselt number and Sherwood number are also computed and analyzed. It is observed that entropy profile increases for all the physical parameters. Moreover, it is found that when the fluid depicts non-Newtonian (Williamson fluid) behavior then it causes reduction in the velocity of fluid, however, non-Newtonian behavior enhances the temperature and nanoparticle concentration profile.

• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.13 no.5
• /
• pp.64-69
• /
• 2014

This article presents machining experiments to assess the relationship between the profile accuracy and the workpiece hardness using a natural diamond tool on an ultra-precision diamond turning machine. The study is intended to secure a corner cube prism pattern for reflective film capable of high-quality outcomes. The optical performance levels and edge images of corner cubes having various hardness levels of the copper-coated layer on a carbon steel plate are analyzed. The hardness of the workpiece has a considerable effect on the profile accuracy. The higher the hardness of the workpiece, the better the profile accuracy and the worse the edge wear of the diamond tool.

• Communications of Mathematical Education
• /
• v.19 no.4 s.24
• /
• pp.805-822
• /
• 2005

In Korea, many local university mathematics faculty knew that the institution faced serious student shortage problems and the restructuring and cut actions for such a mathematics major programs. In general, undergraduate mathematics education in korea is in the crisis. In general, lots of mathematics departments in korea was not prepared for such a severe risk. In this article, university mathematics education and research business are studied in the context of the size of korea-usa population, economy(such as GDP), SCI indices. Korea-usa university mathematics education profile data are presented to compare korea-usa university mathematics education business. Lots of precious data on mathematics education are being helped to prepare for the university mathematics education crisis.

• Structural Engineering and Mechanics
• /
• v.25 no.5
• /
• pp.565-576
• /
• 2007

The article describes a technique for the measurement of the level of complexity of fracture surfaces by the method of vertical sections, and a performed statistical analysis of the effect of profile lines on the fractographic and fractal parameters of fractures, i.e. the profile line development factor, $R_L$, and the fracture surface development factor, $R_S$, (as defined by the cycloid method), as well as the fractal dimension, $D_C$, (as determined by the chord method), and the fractal dimension, $D_{BC}$, (as determined by the box method). The above-mentioned parameters were determined for fracture surfaces of basalt and gravel concretes, respectively, which had previously been subjected to fracture toughness tests. The concretes were made from mixtures of a water/cement ratio ranging from 0.41 to 0.61 and with a variable fraction of coarse aggregate to fine aggregate, $C_{agg.}/F_{agg.}$, in the range from 1.5 to 3.5. Basalt and gravel aggregate of a fraction to maximum 16 mm were used to the tests. Based on the performed analysis it has been established that the necessary number of concrete fracture profile lines, which assures the reliability of obtained testing results, should amount to 12.

• Journal of The Korean Association For Science Education
• /
• v.21 no.5
• /
• pp.795-821
• /
• 2001

This Qualitative study investigated a preservice teacher's developing views of learning with the influence of constructivist epistemology taught in the Math, Science, and Technology Education (MSAT) Master of Education (M. Ed.) preservice teacher education program. The MSAT teacher education program employs constructivist aspects of teacher education and generates applications of constructivism to the practice of teaching, as revealed by faculty interview data. It is important at this point to emphasize that there are significant epistemological and ontological differences between different versions of educational constructivism (i.e., individual, radical, and social constructivism) and that these differences imply different pedagogical practices. For the 16 preservice teachers included in a larger study, the epistemological and ontological characteristics for each teacher's developing views of learning were identified through four in-depth interviews. Data from interviews were used to construct a constructivist profile for each preservice teacher's views of learning (i.e., a profile containing ontological beliefs, epistemological commitments, and pedagogical beliefs). Of the sixteen participants in the larger study, five significantly changed ontological and epistemological beliefs and eleven did not. Profile changes for the five who did change also resulted in changes in their conceptions of science teaching and learning (CSTL). In this article, one of the five teachers case was presented with rich quotes. This case study documents how a preservice teacher transferred his ontological and epistemological beliefs to his pedagogical beliefs and maintained the consistency between his philosophical beliefs and CSTL. It also demonstrated implications that changes in components for an educational constructivist profile have for a preservice teacher's view of himself as teacher. Data indicated the possibility that a constructivist-oriented preservice teacher education program can influence students' conceptions of science teaching and learning by explicitly introducing constructivism as an epistemology rather than as a specific method of instruction. Implications for both instructional practices of teacher education programmes and research are discussed.