Modeling investment priorities for national road improvements: A case study of Korea

The paper addresses specific problems associated with formulating investment priorities for national road improvements in Korea. More specifically, the objectives of the paper are (1) to present a model for formulating investment priorities for road improvements that may be useful to developing countries, (2) to test the model with simplified data for deriving investment priorities for Korea's road improvements, and (3) to learn lessons that can be applicable to other developing countries with particular respect to recommending investment priorities for road improvements. The study results are useful for planners, in developing countries, and also for evaluation analysts in funding institutions who are confronted with evaluating investment priorities for deteriorating road conditions.     

The relationship between physical and chemical weathering indices of granites around Seoul,Korea

In order to assess the relationship between chemical weathering indices and physical properties of granite, physical and chemical analyses were performed on both natural and artificially weathered granite samples from the Seoul area, where the pH of the rainfall occasionally drops to below 5. The results suggest that slake durability, uniaxial compressive strength, Ruxton ratio, Parker index, modified weathering potential index, chemical alteration index and loss on ignition effectively revealed changes of the degree of chemical weathering. However, the study showed no such good correlation between chemical and physical properties except dry density against loss on ignition and modified weathering potential index against uniaxial compressive strength. It is recommended that both physical and chemical indices should be used for the classification of weathering grade for the granites in the Seoul area.

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想像与现实之间--草莓主题公园的空间和理念

在韩国,网络购物(InternetShopping)的环境非常发达。因此,在这种竞争之下,传统的售货柜台不仅要担负展陈商品的基本功能,而且开始更加重视营造消费场所给消费者带来的空间体验,以此提升柜台销售的竞争力。正是在这样的背景之下,SSAMZIE公司策划了“我喜欢草莓(Ilikedalki)”的     

Quantifying inequality in health in the absence of a natural reference group

When quantifying inequality in health, the excess fraction (i.e. the proportional reduction in the outcome in question that would occur if all groups had the same, lowest, risk rate) is an appealing measure. If the population contains a natural, healthiest reference group, the excess fraction is straightforward to estimate. In the absence of an a priori reference group, calculating the excess fraction requires reflection, since using the group with the lowest observed risk rate as reference can lead to erroneous conclusions. This paper proposes a simple simulation procedure for calculating the excess fraction, without fixing a reference group.     

Experimental study on the life prediction of servo motors through model-based system degradation assessment and accelerated degradation testing

The advent of smart factories has resulted in the frequent utilization of industrial robots within factories to increase production automation and efficiency. Due to the increase in the number of industrial robots, it has become more important to prevent any unexpected breakdowns of the factory. As a result, the lifespan prediction of machinery has become a crucial factor because such failures can be directly associated with factory productivity resulting in significant losses. Most of the failures occur within one of the core components of the robot arm, the servo motor, and thus we will focus on the analysis of the servo motor in this study. However, sensor attachment to such equipment is considered difficult due to the dynamic movement of the robot arm, meaning that internal instrumentation should be utilized during analysis. In addition, no definite measure to determine the degradation of the motor exists, and thus a new degradation index is proposed in this study. Therefore, in this study, the lifespan of the servo motor will be estimated through accelerated degradation testing methods based on a new system degradation assessment method, which estimates the fault of the system using observer-based residuals with encoder data obtained from internal instrumentation.     

UNI-Copter: A portable single-rotor-powered spherical unmanned aerial vehicle (UAV) with an easy-to-assemble and flexible structure

Journal of Mechanical Science and Technology - This paper presents the design and modeling of the UNI-Copter, a portable spherical unmanned aerial vehicle (UAV) that is powered by a single rotor....     

Advanced Chamfering Technology for Edge Strengthening

Damage‐free chamfering method for strengthening a glass edge was introduced and its effect on the edge property was discussed in detail. The chamfered surface was evaluated using an optical microscope, a confocal LSM, and a birefringence measurement system. The mechanical properties were characterized by measuring hardness, Young's modulus, and bending strength. The results revealed that the cut edge of 0.55t thin glass sheet containing median cracks and chips was exfoliated uniformly to a thickness of 200 μm, and a smooth edge surface was created (Ra = 0.03 μm). We also reported that the chamfered surface had a compressive stress enabling hardness and Young's modulus increase, and the edge strength improved from 117 to 199 MPa.     

A physical strategy for the preparation of isotactic polypropylene spheres with microsphere and bead–string spherulite morphologies

This study mainly focuses on the formation of isotactic polypropylene (iPP) blend morphologies with microspheres and distinct bead–string spherulites. iPP microspheres have been prepared by a simple and convenient strategy through either an isothermal or a nonisothermal crystallization process based on the macrophase‐separated structure in molten state of iPP/olefin block copolymer (OBC) blend. The dimension of the iPP spheres can be adjusted easily from about 1 µm to >10 µm by controlling the compatibility and annealing conditions. It was found that any of the following three parameters, the molecular structure of OBC (particularly the octene content), molecular weight of iPP, and annealing condition can be rescaled with others in controlling the dimension of the iPP microspheres. The mechanism of the formation of iPP microspheres was studied in detail. Surprisingly, the typical spinodal decomposition morphology with interconnected or thin sheet structure is the precursor of these microspheres. During the subsequent annealing process, it breaks up and further coarsens into spherical structure. In addition, distinct spherulites with a bead–string substructure have been obtained during the isothermal crystallization. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40863.