1-3hit |
Osamu MICHIKAMI Yasuyuki OTA Shinji KIKUCHI
In order to improve the critical current density (Jc) of c-axis-oriented EuBa2Cu3O7 (c-EBCO) thin films deposited on R-plane sapphires (R-Al2O3) with a CeO2 buffer layer, insertion of an Sm2O3 buffer layer and optimization of its deposition condition were attempted. The effects of substrate temperature and film thickness of an Sm2O3 buffer layer on the orientation, crystallinity, surface morphology and superconducting properties of EBCO thin films were examined. As a result, EBCO thin films with Jc = 5.7 MA/cm2 at 77.3 K were obtained on a sapphire with a CeO2(80 )
Shinji KIKUCHI Yoshihiro KANNA Yohsuke ISOZAKI
In recent years, there has been an increasing demand with regard to available elemental services provided by independent firms for compositing new services. Currently, however, whenever it is difficult to maintain the required level of quality of a new composite web service, assignment of the new computer's resources as provisioning at the data center is not always effective, especially in the area of performance for composite web service providers. Thus, a new approach might be required. This paper presents a new control method aiming to maintain the performance requirements for composite web services. There are three aspects of our method that are applied: first of all, the theory of constraints (TOC) proposed by E.M. Goldratt ; secondly, an evaluation process in the non-linear feed forward controlling method: and finally multiple trials in applying policies with verification. In particular, we will discuss the architectural and theoretical aspects of the method in detail, and will show the insufficiency of combining the feedback controlling approach with TOC as a result of our evaluation.
Shinji KIKUCHI Satoshi TSUCHIYA Kunihiko HIRAISHI
Managing the configurations of complex systems consisting of various components requires the combined efforts by multiple domain experts. These experts have extensive knowledge about different components in the system they need to manage but little understanding of the issues outside their individual areas of expertise. As a result, the configuration constraints, changes, and procedures specified by those involved in the management of a complex system are often interrelated with one another without being noticed, and their integration into a coherent procedure for configuration represents a major challenge. The method of synthesizing the configuration procedure introduced in this paper addresses this challenge using a combination of formal specification and model finding techniques. We express the knowledge on system management with this method, which is provided by domain experts as first-order logic formulas in the Alloy specification language, and combine it with system-configuration information and the resulting specification. We then employ the Alloy Analyzer to find a system model that satisfies all the formulas in this specification. The model obtained corresponds to a procedure for system configurations that satisfies all expert-specified constraints. In order to reduce the resources needed in the procedure synthesis, we reduce the length of procedures to be synthesized by defining and using intermediate goal states to divide operation procedures into shorter steps. Finally, we evaluate our method through a case study on a procedure to consolidate virtual machines.