Optimal Rendezvous L-Algorithms for Asynchronous Mobile Robots with External-Lights

We study the Rendezvous problem for two autonomous mobile robots in asynchronous settings with persistent memory called light. It is well known that Rendezvous is impossible in a basic model when robots have no lights, even if the system is semi-synchronous. On the other hand, Rendezvous is possible if robots have lights of various types with a constant number of colors. If robots can observe not only their own lights but also other robots\u27 lights, their lights are called full-light. If robots can only observe the state of other robots\u27 lights, the lights are called external-light. This paper focuses on robots with external-lights in asynchronous settings and a particular class of algorithms called L-algorithms, where an L-algorithm computes a destination based only on the current colors of observable lights. When considering L-algorithms, Rendezvous can be solved by robots with full-lights and three colors in general asynchronous settings (called ASYNC) and the number of colors is optimal under these assumptions. In contrast, there exist no L-algorithms in ASYNC with external-lights regardless of the number of colors. In this paper, extending the impossibility result, we show that there exist no L-algorithms in so-called LC-1-Bounded ASYNC with external-lights regardless of the number of colors, where LC-1-Bounded ASYNC is a proper subset of ASYNC and other robots can execute at most one Look operation between the Look operation of a robot and its subsequent Compute operation. We also show that LC-1-Bounded ASYNC is the minimal subclass in which no L-algorithms with external-lights exist. That is, Rendezvous can be solved by L-algorithms using external-lights with a finite number of colors in LC-0-Bounded ASYNC (equivalently LC-atomic ASYNC). Furthermore, we show that the algorithms are optimal in the number of colors they use

Shape from shading with interreflections under proximal light source - 3D shape reconstruction of unfolded book surface from a scanner image

We address the problem to recover the 3D shape of an unfolded book surface from the shading information in a scanner image. From a technical point of view, this shape from shading problem in real world environments is characterized by (1) proximal light source, (2) interreflections, (3) moving light source, (4) specular reflection, and (5) nonuniform albedo distribution. Taking all these factors into account, we first formulate the problem based on an iterative nonlinear optimization scheme. Then we introduce piecewise polynomial models of the 3D shape. Image restoration experiments for a real book surface demonstrated that geometric and photometric distortions are almost completely removed by the proposed method</p

Spatial Characteristics of Production and Delivery of Films in Mumbai, India

本研究はインド映画産業，特にその中心であるムンバイー映画産業（ボリウッド）の発展過程，生産・流通システムとその空間構造を明らかにした。ムンバイーは，パールシー資本とパールシー演劇の存在，ヒンディー語映画の制作，インド全土からの人材流入，反社会的勢力からの資金流入，1990年代後半からの政府支援などにより，インド映画産業の中心地として発展してきた。ムンバイーでの映画制作は，プロデューサーや俳優の住居/事務所やスタジオが集積するムンバイー市北郊を中心に行われる。しかし近年，ヒンディー語映画を中心に，撮影工程は経済的理由と創造的理由から地理的に拡散する傾向にあり，録音・編集工程の一部も技術的理由から国内他都市でも担われるようになっている。ヒンディー語映画の配給は1990年代以降，12区域に地理的に区分されるインド国内市場に加えて，国外市場と衛星テレビ市場が急成長してきた。This research clarified the spatial characteristics of the development, production, and delivery of films in Mumbai, India, popularly known as “Bollywood”. Bollywood originated from and was influenced by Parsee merchants and the Parsee theater, the production of Hindi cinema in the 1930s, the influx of performers and technicians from around India in the late 1940s, the inflow of funds from organized crime in the 1940s, and support from the government since the late 1990s. Most Bollywood films are produced in Mumbai’s northern suburbs, where most producers and actors live and most studios are located. Bollywood films are now often shot outside Mumbai, including in foreign cities, for economic and artistic reasons. Sound recording and film editing tend to be done in other cities, for example, Hyderabad, Bangalore, and Delhi, for technical reasons. Bollywood films are distributed throughout the 12 major areas of India, while overseas markets and satellite TV broadcasting have been rapidly growing since the 1990s.本研究の骨子は，2012年度HINDAS第2回研究集会（2012年8月10日，於. 広島大学）および日本地理学会2013年度秋季学術大会（2013年9月28日，於. 福島大学）において発表した。また本研究の実施にあたり，科学研究費（基盤研究(B)）「インド成長産業のダイナミズムと空間構造」（課題番号 23320185，研究代表者 友澤和夫）を使用した