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Search Results: 1 - 10 of 1264 matches for " Hideki Takebayashi "
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Study on Surface Heat Budget of Various Pavements for Urban Heat Island Mitigation
Hideki Takebayashi,Masakazu Moriyama
Advances in Materials Science and Engineering , 2012, DOI: 10.1155/2012/523051
Abstract: The surface heat budgets of various pavement surfaces are studied with the aim of mitigating the urban heat island effect. In this study, the thermal characteristics of pavements are examined using data from observations. The net radiation, surface temperature, temperature under the surface, conduction heat flux, and core weight for each experimental surface are recorded, together with the weather conditions at the time of observation. The latent heat flux is estimated from the observed weight of the cores. The surface heat budget under the same weather conditions is examined, and the sensible heat flux from each target surface is calculated. The parameters that influence the surface heat budget, for example, solar reflectance (albedo), evaporative efficiency, heat conductivity, and heat capacity, are examined. On a typical summer day, the maximum reduction in the sensible heat flux from that on a normal asphalt surface is about 150?W/m2 for an asphalt surface with water-retaining material and about 100?W/m2 for a cement concrete surface with water-retaining material, depending on the albedo of each surface. 1. Introduction The purpose of this study is to investigate the urban heat island mitigation effect achieved by conversion from an asphalt pavement surface to another pavement surface for ground surface improvement, which is an established urban heat island mitigation technique. Various kinds of pavements were constructed experimentally for the purpose of investigating their effect on urban heat island mitigation by analyzing the surface heat budget. The urban heat island mitigation effect is discussed from the viewpoint of the sensible heat flux reduction for each pavement. Urban heat island mitigation technologies focus on the improvement of urban surface materials on roads, roofs, and walls. For example, roads and roofs coated with high-reflectance paint are called cool roofs and cool pavements by Akbari et al. [1]. According to their estimates, the annual balances in the saving in cooling cost and the increase in heating cost obtained by introducing cool roofs are $35 million in Los Angeles, $16 million in New York, and $10 million in Chicago. However, fewer studies have been carried out on roads as compared to those on green roofs [2–7], green parks [8–12], and green plantings [13–15]. In Japan, several studies have been carried out to evaluate the performance of pavements designed to have a beneficial environmental impact [16–20]. However, those studies have evaluated each technology separately and discussed only the reduction in surface
Dynamic Effect of Low-Cost Entry on the Conduct Parameter: An Early-Stage Analysis of Southwest Airlines and America West Airlines  [PDF]
Hideki Murakami
Modern Economy (ME) , 2013, DOI: 10.4236/me.2013.44032
Abstract:

The purpose of this research is to investigate the dynamic changes in the competition between air carriers by applying a revised conduct parameter method. We examine the cases of Southwest Airlines and America West Airlines due to the availability of data. Our interests are in what fashion a low-cost carrier entered the market, how the rival reacted, and whether the fashions of competition between two types of air carrier remained stable as time passed. Our empirical results show that the fashions of competition fell between Cournot and “P = MC” competition, and competitive fashions were sometimes stable but sometimes not.

Efficient Frontier via Production Functions and Mechanization  [PDF]
Hideki Nakamura
American Journal of Operations Research (AJOR) , 2017, DOI: 10.4236/ajor.2017.71004
Abstract: This study attempts to reconcile data envelopment analysis (DEA) with the production function approach in economics. We examine not only the inputs of capital and labor, but also the ranges of these inputs in production process steps, and endogenously derive a Leontief production function. The Leontief production functions shift northeasterly owing to mechanization, which is the replacement of labor inputs by capital inputs in some steps. Consequently, we describe the efficient frontier as the convex hull of the Leontief production functions. Furthermore, we consider the possibility of efficient production below the efficient frontier.
An Equilibrium Asset Pricing Model under the Dual Theory of the Smooth Ambiguity Model  [PDF]
Hideki Iwaki
Journal of Mathematical Finance (JMF) , 2018, DOI: 10.4236/jmf.2018.82031
Abstract: This paper considers an equilibrium asset pricing model in a static pure exchange economy under ambiguity. Ambiguity preference is represented by the dual theory of the smooth ambiguity model [6]. We show the existence and the uniqueness of the equilibrium in the economy and derive the state price density (SPD). The equilibrium excess return, which can be seen as an extension of the capital asset pricing model (CAPM) under risk to ambiguity, is derived from the SPD. We also determine the effects of ambiguity preference on the excess returns of ambiguous securities through comparative statics of the SPD.
Factor Substitution and Employment  [PDF]
Hideki Nakamura
Modern Economy (ME) , 2018, DOI: 10.4236/me.2018.97074
Abstract: This paper explores how employment among an educated workforce depends on production technology represented by factor substitution and factor-augmenting technical progress. We consider a variant of the Diamond overlapping generations model that can explain the empirical finding about the elasticity of substitution being less than unity observed in some developed economies. Depending on factor substitution, a decline in the wage rate has positive and negative effects on employment. When the elasticity of substitution is less than unity, a low wage rate can imply a low employment rate as well as a low human capital level. Given the elasticity of substitution, being less than unity, labor-augmenting technical progress can decrease the employment rate and human capital level via a decrease in the marginal product of labor.
Analysis of Proprioception of Hip Joint in Total Hip Arthroplasty  [PDF]
Hitoshi Onishi, Satoshi Nagoya, Tsuneo Takebayashi, Toshihiko Yamashita
Open Journal of Orthopedics (OJO) , 2017, DOI: 10.4236/ojo.2017.72007
Abstract: Introduction: The instability of the joint is classified roughly into mechanical and functional. It is reported that the postoperative dislocation often occurs by the posterior approach of the THA and may be caused by functionality instability due to the injury of the periarticular soft tissue. We analyzed the joint position sense of the hip according to an approach of the THA and examined effect to give postoperative dislocation. Materials & Methods: 92 patients (184 hip joints) who received THA in our hospital were selected in the study. Cases in which position sensation measurements were insufficient were excluded. As for the classification, the posterior approach (PL groups) was 39 hips, anterolateral approach (AL groups) was 30 hips, and control group was 37 hips. Results: There was no significant difference between the AL group and PL group in the absolute reproduction angle error score (ARAES). The relative reproduction angle error scores (RRAES) for passive internal and external rotations and active internal rotation were significantly lower in the AL and control groups than the PL group. Discussion: This study was suggested that the hip joint position sense in the AL group was better retained for the preservation of the soft tissue.
Multiple Equilibria between Fertility Rates and Pension Levels Based on the Target Level of Government Debt  [PDF]
Hideki Nakamura, Masaya Yasuoka
Theoretical Economics Letters (TEL) , 2011, DOI: 10.4236/tel.2011.13020
Abstract: We show that when the government has a target debt level, multiple equilibria exist in the relationship between fertility rates and pension levels. One is associated with a high fertility rate and a high pension level. The other is associated with a low fertility rate and a low pension level. If the government fails to provide adequate security for individuals during their retirement years, it would result in a failure of coordination between the government and individuals.
Effect of Surface Texturing on Lubricating Condition under Point Contact Using Numerical Analysis  [PDF]
Yuji Ohue, Hideki Tanaka
Engineering (ENG) , 2013, DOI: 10.4236/eng.2013.54050
Abstract:

The contact fatigue life of machine elements is affected by pitting, wear and so on, under heavier loading conditions. Increasing the fatigue life requires mainly the improvements of lubricating condition, operating condition and materials. In order to improve the lubricating condition, it is necessary to investigate the relation of the microscopic surface texturing and the contact modes of machine elements. In this paper, thus, the pressure and oil film thickness of the contact between sphere and the plate with 5 kinds surface texturing were calculated using a commercial software based on Reynolds equation. There was sufficient evidence to suggest that the dimple shape was the optimum texturing to increase the lubricating condition.

An Empirical Study of Option Prices under the Hybrid Brownian Motion Model  [PDF]
Hideki Iwaki, Lei Luo
Journal of Mathematical Finance (JMF) , 2013, DOI: 10.4236/jmf.2013.32033
Abstract:

In this paper, we mainly discuss an empirical study of option prices under the hybrid Brownian motion model developed by [1]. In a specific case of parameters, we have a simple transition probability density function that has a fattailed feature as time passes. We show some empirical evidences that the feature of the model reflects the real market price movements in Japanese stock market. Furthermore, we make a performance comparison between the hybrid model and the BS model using Nikkei 225 call options. In general our results show that the hybrid model is slightly better than the BS model.

An Optimal Life Insurance Policy in the Continuous-Time Investment-Consumption Problem  [PDF]
Hideki Iwaki, Yusuke Osaki
Journal of Mathematical Finance (JMF) , 2013, DOI: 10.4236/jmf.2013.32029
Abstract:

This paper considers an optimal life insurance for a household subject to mortality risk. The household receives wage income continuously, which could be terminated by unexpected premature loss of earning power. In order to hedge the risk of losing income stream, the household enters a life insurance contract. The household may also invest their wealth into a financial market. Therefore, the problem is to determine an optimal insurance/investment/consumption strategy. To reflect a real-life situation better, we consider an incomplete market where the household cannot trade insurance contracts continuously. We provide explicit solutions in a fairly general setup.

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