Yasushi TAUCHI

3D SLAM (Simultaneous Localization and Mapping) is a technique for creating circumstance maps which are usable for measuring the environments and providing navigation information. One of the problems in 3D SLAM is computational efficiency of inserting new points into the circumstance map, since the efficiency is essential for keeping the quality and quantity of the obtained circumstance map and keeping the stability of the mapping procedure. This study focuses on how to improve the computational efficiency of 3D SLAM as a UGV (unmanned ground vehicle) application. We employ a sophisticated and well-organized 3D SLAM package, ETHZASL-ICP-Mapper, as a fundamental implementation. After analyzing the reason why the efficiency becomes decreased through the mapping procedure, we point out main two problems. Then we propose two approaches for overcoming these problems. The first approach is to divide the circumstance maps into sub-grid maps. The second approach is to alternate the k-d tree data structure in the point density control with a voxel grid data structure. The improvements are discussed based on the comparative experimental results.

本論文では，山口大学メディア基盤センターにおいて行っているサーバ室の空調に対する省エネルギーの取り組みについての紹介を行う．具体的には，既存の空調施設を利用した外気取り込みの効果の検証，サーバ室内の温度分布計測および気流制御の方策に関する検討を行う This paper introduces an action of energy saving for air conditioner of server room tried in media and information technology center of Yamaguchi University. Verification of effectiveness of the open air utilization for an existing facilities, measurement results of a temperature distribution in a server room and discussions of air-flow control scheme are presented.

Using a mesh grid bias method for plasma parameter control, volume production of hydrogen negative ions H" is studied in pure hydrogen rf plasmas. Relationship between the extracted H" ion currents and plasma parameters is discussed. Both high and low electron temperature Tc plasmas are produced in the separated regions when the grid is negatively biased. In addition, with changing grid potential Vg, values of nc increase while Tc decrease in their values. The negative ion production depends strongly on the grid potential and related plasma conditions. It is also confirmed that grid bias method is more effective than the so-called magnetic filter method to optimize plasma parameters for H" production. Production of deuterium negative ions D" is also studied briefly. © 2009 American Institute of Physics.

Using a grid bias method for plasma parameter control, volume production of hydrogen negative ions H^- is studied in pure hydrogen rf plasmas. Relationship between the extracted H^? ion currents and plasma parameters is discussed. It is confirmed that both high and low electron temperature T_e plasmas are produced in the separated regions when the grid is negatively biased. In addition, with changing grid potential V_g, values of n_e increase while T_e decrease in their values. The negative ion production depends strongly on the grid potential and related plasma conditions.

This chapter discusses the varying magnetic field intensity of the magnetic field (MF), plasma parameter control in hydrogen (H2), deuterium (D2) plasmas, and its influence on H/D production. The relationship between H/D density distribution and plasma parameter control is discussed. The dependence of extracted H/D currents on H-/D- densities in the source is also discussed. To understand H/D negative ion formation mechanism and behavior of H/D ions in volume negative ion sources, axial distributions of H-/D densities in the source are measured directly by laser photo detachment method. H and D densities have different spatial distributions, respectively, corresponding to those different plasma parameter conditions. Plasma parameters are changed almost in the same manner by varying the magnetic field intensity of the MF. Axial distributions of plasma parameters across the MF affect electron detachment (ED) process more strongly than dissociative attachment (DA) process. © 2005 Elsevier Ltd. All rights reserved.