Search

経済学 / Economics, In DEA, we have two measures of technical efficiency with different characteristics: radial and non-radial. In this paper we compile them into a composite model called “epsilon-based measure (EBM).” For this purpose we introduce two parameters which connect radial and non-radial models. These two parameters are obtained from the newly defined affinity index between inputs or outputs along with principal component analysis on the affinity matrix. Thus, EBM takes into account diversity of input/output data and their relative importance for measuring technical efficiency., http://www.grips.ac.jp/list/facultyinfo/tone_kaoru/

This study introduces a new scheme of data envelopment analysis (DEA) named cost gradient measure (CGM) to evaluate technical efficiency. In this model, we can obtain more cost conscious technical efficiency than those by other traditional DEA models such as CCR[7] and slacks-based measure (SBM) [19]. In addition, the CGM can avoid shortcomings of these traditional models, i.e. factor inefficiency scores can be measured for each input as opposed to CCR and SBM models. In this study, we show the generality of CGM that it includes CCR as a special case; and compare the CGM result with those of the other DEA models using illustrative data, and clarify favorite features of this model. In addition, we also apply these models to Japanese electric utilities and explain the characteristics of their results., http://www.grips.ac.jp/list/facultyinfo/tone_kaoru/, http://www.grips.ac.jp/list/jp/facultyinfo/yoshida_yuichiro/

経済学 / Economics, Firstly, we discuss differences between Farrell and Pareto-Koopmans efficiency measures in DEA, and propose a composite method for discriminating them. Then, we extend the method to so-called “epsilon based-measure (EBM).” The EBM can examine the robustness and stability of efficiency measure of DMUs regarding parametric change of input multiplier variables. Lastly, we propose a scheme for selecting an appropriate value of epsilon with recourse to actual cost shares of input resources., http://www.grips.ac.jp/list/facultyinfo/tone_kaoru/

総合政策 / Multi Disciplinary policy studies, In data envelopment analysis, there are several methods for measuring efficiency change over time, e.g. the window analysis and the Malmquist index. However, they usually neglect carry-over activities between consecutive two terms. These carry-overs play an important role in measuring the efficiency of decision making units in each term as well as over the whole terms based on the long-term viewpoint. Dynamic DEA model proposed by Färe and Grosskopf is the first innovative contribution for such purpose. In this paper we develop their model in the slacks-based measure (SBM) framework, called Dynamic SBM (DSBM). The SBM model is non-radial and can deal with inputs/outputs individually, contrary to the radial approaches that assume proportional changes in inputs/outputs. Furthermore, according to the characteristics of carry-overs, we classify them into four categories, i.e. desirable, undesirable, free and fixed. Desirable carry-overs correspond, for example, to profit carried forward and net earned surplus carried to the next term, while undesirable carry-overs include, for example, loss carried forward, bad debt and dead stock. Free and fixed carry-overs indicate, respectively, discretionary and non-discretionary ones. We develop Dynamic SBM models that can evaluate the overall efficiency of decision making units for the whole terms as well as the term efficiencies., http://www.grips.ac.jp/list/facultyinfo/tone_kaoru/

総合政策 / Multi Disciplinary policy studies, It has been pointed out that DEA scores may be influenced by several external environmental factors, which are uncontrollable for DMUs. It implies that the DEA efficiency score without data adjustment might be biased and impractical for measuring genuine management efficiency. Therefore it is essential to eliminate uncontrollable effects from DEA scores and evaluate “pure” managerial efficiency for DMUs. In an effort to solve this problem, we employ a multi-stage data adjustment procedure using DEA and regression models, which is originally proposed by Fried et al. [1999] consisting of four stages. In this study, we further modify this procedure by introducing newly developed devices in each stage; Connected Slacks-Based Measure (CSBM) model at the first and fourth stages, the Tobit model with DMU dummies at the second stage, and a data tuning procedure at the third stage. Then we decompose the technical inefficiency into three factors, i.e. environmental effects, time shift effects and pure technical inefficiency. Lastly, we apply this procedure to the electric power utilities in Japan and the US and compare their pure technical efficiency and causes of inefficiency., http://www.grips.ac.jp/list/facultyinfo/tone_kaoru/

総合政策 / Multi Disciplinary policy studies, Liberalization of the electric power industry has been underway in various countries. Under this situation, it is necessary for electric power companies to improve their management efficiency in order to survive in a competitive market. This study examines management efficiency of vertically integrated electric companies, which consist of several divisions, such as generation, transmission, distribution and so forth. Previous studies mainly focused on efficiency of only a specific division independently. However, we should evaluate firm-level management efficiency based on divisional efficiencies, because these divisions are closely linked each other. For measuring firm-level efficiency, we apply a network DEA model that considers a streamlined relationship among divisions under vertical integration. Furthermore we newly proposed a constrained network DEA model to obtain more practical efficiency index., http://www.grips.ac.jp/list/facultyinfo/tone_kaoru/

After pointing out shortcomings of the traditional adjustment scheme for combining SFA results for use in DEA in the three stage approach, we propose a new scheme. We demonstrate the effect of this adjustment formula using an electric utility data set., http://www.grips.ac.jp/list/facultyinfo/tone_kaoru/

Data envelopment analysis (DEA) has been utilized worldwide for measuring efficiencies of banks, telecommunications, electric utilities and so forth. Yet, the existing models have some well known shortcomings that limit their usefulness. In DEA we have two fundamental approaches to measuring efficiency with very different characteristics; radial and non-radial. We demonstrate a method for linking these two approaches in a unified framework called Connected-SBM. It includes two scalar parameters, and by changing the parameter values we can relocate the analysis anywhere between the radial and the non-radial models. An appropriate choice of these parameters can overcome the key shortcomings inherent in the two approaches, namely, proportionality and mixed patterns of slacks., http://www.grips.ac.jp/list/facultyinfo/tone_kaoru/

Prior to the 1990s, the electric power industry was highly regulated in worldwide bases. Under a new policy of open markets and introducing competition into the industry, efficient management has become a requirement for these companies. The purpose of this study is to examine the divisional efficiency of multi-functioned vertically integrated companies in order to optimize overall management efficiency. For this purpose, cost data of each division is applied as input to the Slacks-Based Measure(SBM) model, which provides an efficiency index for each input factor based on slacks as well as to provide an efficiency index for overall management. Furthermore, considering the important role of cost share structure, this study introduces a slightly modified SBM, namely, the Weighted SBM (WSBM), which directly incorporates weight among inputs into the objective function. The results reveal that the generation division has a significant influence on overall cost, while the impact of the other four divisions is limited and reflects their cost shares.

In any competitive set up, policy recommendations based on elasticity parameters have assumed greater significance for the firm's financial viability and success. So there is a need to examine with more prudence the elasticity estimates obtained from various parametric as well nonparametric methods. The main aim of this paper is first to critically examine these methods in order to shed light on what seems to be missing, and then to proceed by developing an empirically demanding ecompassing measure of scale elasticity. All these measures, which are finally applied to a panel data of US electric companies, constitute the empirical premise of this paper., Research supported by Grant-in-Aid for Scientific Research (C) Japan Society for the Promotion of Science, First version: "A Comparative Evaluation of Parametric and Nonparametric Methods to Estimating Degree of Scale Economies" Tone, Kaoru; Sahoo, Biresh K., 2002/7/31, http://www.grips.ac.jp/list/facultyinfo/tone_kaoru/

This paper presents a new formula for decomposing cost efficiency into technical, price, and allocative efficiencies in an environment marked by the fact that unit input prices differ among certain enterprises. We employed this formula for comparing cost efficiency between Japan-US electric power companies and found a significant difference in the price-based efficiency between the two countries; however, negligible differences were found in the technical and allocative efficiencies., Research supported by Grant-in-Aid for Scientific Research (C) Japan Society for the Promotion of Science, http://www.grips.ac.jp/list/facultyinfo/tone_kaoru/

International audience; The Great East Japan earthquake occurred on March 11, 2011, at 1446, and the subsequent tsunami led Tokyo Electric Power Company's (TEPCO's) Fukushima Daiichi Nuclear Power Station (NPS) beyond a design-basis accident. After the accident, the Japanese government and TEPCO compiled a roadmap toward an early resolution to the accident including, among the main activities, the employment and improvement of existing severe accident (SA) computer codes. In the member countries of the Organisation for Economic Co-operation and Development/Nuclear Energy Agency (OECD/NEA), SA codes were developed after the accident at Three Mile Island Unit 2 and widely employed to assess NPS status in the postulated SA conditions. Therefore, working plans have been set up with the country members of the OECD/NEA to apply existing SA codes to analyze the accidents at the Fukushima Daiichi NPS Units 1, 2, and 3 and support the decommissioning, constituting an international program named Benchmark Study of the Accident at the Fukushima Daiichi Nuclear Power Station (BSAF). The objectives of the BSAF project are to analyze the accident progression of Fukushima Daiichi NPS, to raise the understanding of SA phenomena, to contribute to the improvement of the methods and models of the SA codes, and to define the status of the distribution of debris in the reactor pressure vessels and primary containment vessels for decommissioning. The present technical paper summarizes the achievements obtained through a comparison of the results, emphasizing the portions of the accident where all the participants reached a common consensus and identifying still open questions where future work should be directed. Consensus exists on the current condition of Unit 1, where a large fraction of the fuel is assumed to have relocated ex-vessel. On the other hand, larger uncertainties exist for Units 2 and 3, where in-vessel and ex-vessel scenarios produce a reasonable prediction of the accident progression.

Publisher Copyright: Author Anatomical human models have been widely used in the assessment of induced field strength for low-frequency (LF) electromagnetic field exposure. One bottleneck is the assignment of a single electrical conductivity to all the voxels of the corresponding tissue. This simplification is known to cause computational artifact; therefore, a large reduction factor was considered in international guidelines and standards. Recently, head models with nonuniform conductivities generated using deep learning networks were proposed, and the effect on the reduction of staircasing artifacts was demonstrated. If the effectiveness of the models is confirmed for different models and codes, it would be useful to derive the relationship between the internal and external field strengths needed for setting the exposure limit. The Subcommittee 6 of the IEEE International Committee on Electromagnetic Safety Technical Committee 95 launched a working group to conduct the first intercomparison study of the induced electric field in learning-based head models exposed to LF magnetic fields. Seven international research groups have cooperated in this joint study. The highest relative difference (RD) in averaged electric fields was 23%, which is attributable to the difference caused the by scalar potential finite difference (SPFD) method and finite element method. Except for one group, the RDs in the 100th and 99th percentile values of the averaged electric field using the SPFD method with different solvers and codes were below 1%, indicating that the uncertainty due to different codes is sufficiently small under the same exposure scenarios. The findings would be informative for future revision of exposure limits and reduction factors in the exposure standard, which is closely related to computational uncertainty.

International audience; We present a self-deformable flexible tweezer capable of simultaneous mechanical handling and electrical measurements. The tweezer has a soft cantilever with the dimensions 2 mm ×8 mm × 75- 100 μm , and undergoes self-deformation. The device is shown to be successfully capable of detecting electrical signals by gently touching the surface and grasping a spherical bead. The device demonstrated the lowest working voltage (1.5 VDC), force suitable for soft gripping, and curvature radius of 2 mm, that was one of the smallest values compared to that of similar state-of-the-art devices. The device was fabricated using a unique and highly reliable process that was specifically developed to produce flexible cantilevers with novel ionic polymer-metal composites (IPMCs). The materials used were poly(vinylidene fluoride-co-trifluoroethylene) (PVDF-TrFE) and an ionic liquid (IL). The PVDF-TrFE/IL gel was prepared using acetone as the solvent and the gel was coated with silver nanowires as the electrodes. The actuator with a length of 8 mm and containing 50 wt% IL yielded the largest bending displacement of 7 mm and minimum curvature radius of 2 mm at 1.5 VDC. [2022-0026]

In the framework of the model inter-comparison study - Asia Phase II (MICS2), where eight models are compared over East Asia, this paper studies the influence of different parameterizations used in the aerosol module on the aerosol concentrations of sulfate and nitrate in PM10. An intracomparison of aerosol concentrations is done for March 2001 using different configurations of the aerosol module of one of the model used for the intercomparison. Single modifications of a reference setup for model configurations are performed and compared to a reference case. These modifications concern the size distribution, i.e. the number of sections, and physical processes, i.e. coagulation, condensation/evaporation, cloud chemistry, heterogeneous reactions and sea-salt emissions. Comparing monthly averaged concentrations at different stations, the importance of each parameterization is first assessed. It is found that sulfate concentrations are little sensitive to sea-salt emissions and to whether condensation is computed dynamically or by assuming thermodynamic equilibrium. Nitrate concentrations are little sensitive to cloud chemistry. However, a very high sensitivity to heterogeneous reactions is observed. Thereafter, the variability of the aerosol concentrations to the use of different chemistry transport models (CTMs) and the variability to the use of different parameterizations in the aerosol module are compared. For sulfate, the variability to the use of different parameterizations in the aerosol module is lower than the variability to the use of different CTMs. However, for nitrate, for monthly averaged concentrations averaged over four stations, these two variabilities have the same order of magnitude., Comment: Atmospheric Environment (2007) in press

This paper studies two high-pollution episodes over Greater Tokyo: 9 and 10 December 1999, and 31 July and 1 August 2001. Results obtained with the chemistry-transport model (CTM) Polair3D are compared to measurements of inorganic PM2.5. To understand to which extent the aerosol processes modeled in Polair3D impact simulated inorganic PM2.5, Polair3D is run with different options in the aerosol module, e.g. with/without heterogeneous reactions. To quantify the impact of processes outside the aerosol module, simulations are also done with another CTM (CMAQ). In the winter episode, sulfate is mostly impacted by condensation, coagulation, long-range transport, and deposition to a lesser extent. In the summer episode, the effect of long-range transport largely dominates. The impact of condensation/evaporation is dominant for ammonium, nitrate and chloride in both episodes. However, the impact of the thermodynamic equilibrium assumption is limited. The impact of heterogeneous reactions is large for nitrate and ammonium, and taking heterogeneous reactions into account appears to be crucial in predicting the peaks of nitrate and ammonium. The impact of deposition is the same for all inorganic PM2.5. It is small compared to the impact of other processes although it is not negligible. The impact of nucleation is negligible in the summer episode, and small in the winter episode. The impact of coagulation is larger in the winter episode than in the summer episode, because the number of small particles is higher in the winter episode as a consequence of nucleation., Comment: Journal of Geophysical Research D: Atmospheres (15/05/2007) in press

International audience; Five transport coefficients of the cuprate superconductor Bi 2 Sr 2−x La x CuO 6+δ were measured in the normal state down to low temperature, reached by applying a magnetic field (up to 66 T) large enough to suppress superconductivity. The electrical resistivity, Hall coefficient, thermal conductivity, Seebeck coefficient, and thermal Hall conductivity were measured in two overdoped single crystals, with La concentration x = 0.2 (T c = 18 K) and x = 0.0 (T c = 10 K). The samples have dopings p very close to the critical doping p where the pseudogap phase ends. The resistivity displays a linear dependence on temperature whose slope is consistent with Planckian dissipation. The Hall number n H decreases with reduced p, consistent with a drop in carrier density from n = 1 + p above p to n = p below p. This drop in n H is concomitant with a sharp drop in the density of states inferred from prior NMR Knight shift measurements. The thermal conductivity satisfies the Wiedemann-Franz law, showing that the pseudogap phase at T = 0 is a metal whose fermionic excitations carry heat and charge as do conventional electrons. The Seebeck coefficient diverges logarithmically at low temperature, a signature of quantum criticality. The thermal Hall conductivity becomes negative at low temperature, showing that phonons are chiral in the pseudogap phase. Given the observation of these same properties in other, very different cuprates, our study provides strong evidence for the universality of these five signatures of the pseudogap phase and its critical point.

International audience; This is the third part of the three part paper describing the accidents at the Fukushima Daiichi nuclear power station as analyzed in the Phase 2 of the OECD/NEA project “Benchmark Study of the Accident at the Fukushima Daiichi Nuclear Power Plant” (BSAF). In this paper, we describe the accident progression in unit 3. Units 1 and 2 are discussed in parts 1 and 2 of this series of papers. In the BSAF project, eight organizations from five countries (CRIEPI, IAE, JAEA and NRA, Japan; IRSN France; PSI, Switzerland; SNL, USA; VTT, Finland) analyzed severe accident scenarios for Unit 3 at the Fukushima Daiichi site using different severe accident codes (ASTEC, MAAP, MELCOR, SAMPSON, THALES). The present paper for Unit 3 describes the findings of the comparison of the participants’ results against each other and against plant data, the evaluation of the accident progression and the final status inside the reactors. Special focus is on the status of the reactor pressure vessel, melt release and fission product release and transport. Unit 3 specific aspects, e.g., the complicated accident progression following repeated containment venting actuations and attempts at coolant injection at the time of the major core degradation, are highlighted and points of consensus as well as remaining uncertainties and data needs will be summarized. Fission product transport is analyzed, and the calculation results are compared with dose rate measurements in the containment. The release of I-131 and Cs-137 to the environment is compared with analysis conducted using WSPEEDI code.