We propose an approach to generating virtual cities that vary dynamically over time, focusing on the layout of artificial elements such as building, roads, and traffic lights. We first define an environment vector as the amount of features reflecting economic and functional activities of city's residents in each block surrounded by roads. Our method generates virtual cities by deleting and locating buildings from two points of view: building layouts using vectors themselves to generate cityscapes, and time-varying using changes of vectors to vary cityscapes. We demonstrate that our method can represent features and generate various cityscapes that vary over time.

We propose an approach to generating virtual cities that vary dynamically over time, focusing on the layout of artificial elements such as building, roads, and traffic lights. We first define an environment vector as the amount of features reflecting economic and functional activities of city's residents in each block surrounded by roads. Our method generates virtual cities by deleting and locating buildings from two points of view: building layouts using environment vectors, which can represent features, themselves to generate cityscapes, and time-varying using changes of vectors to vary cityscapes. We introduce three modules of our city model briefly, and describe how our system relocates buildings in each block. In addition, we demonstrate that our method can represent features and generate various cityscapes that vary over time.

This paper describes a problem for rearranging floor layouts and proposes a system which generates a plan and schedule synchronously. Rearrangement of floor layout (RAFL) is a search problem, which consists of pre- and post-change layouts of objects, workers, and a work hour limit. The goal in solving RAFL is to find a pair of rearrangement plan and its schedule. RAFL deals with planning and scheduling simultaneously, whereas a schedule is usually determined after a plan is found. In RAFL, even if an optimal plan is obtained in advance, a schedule consisting of its elements may not be necessarily feasible. The proposed system uses constraints to represent the required knowledge and tree search algorithm. The system is interactive and informs the users of their search progress. The users may interrupt a search at any time to correct the system if the search is too slow or reaches an insufficient solution. Experimental results show that the system interacted with the user can find a valid solution in scores of minutes, where the time to solve is considerably reduced.

This paper presents an efficient walk-through animation with two images of the same scene. We suggest a new virtual navigation technique which enables natural scene transformation when the viewpoint changes in the parallel direction as well as in the depth direction. In our method, view morphing is employed only in foreground objects, and background scene perceived carelessly is mapped into cube-like 3D model as in TIP (tour into the picture), so as to save detail 3D reconstruction cost and improve visual realism simultaneously. To do this, we define a new camera transformation between two images from the relationship of spidery mesh transformation and its corresponding view change. The result animation demonstrates the efficiency of our method.

Many stochastic search algorithms developed to solve large-scale constraint satisfaction problems in a practical time have the drawback of becoming stuck in locally minimal solutions which are not acceptable as solutions. We analyze a stochastic search algorithm from the viewpoint of local constraint structures of local minima. Using the graph-coloring problem with three colors, we studied the local graph structures around which concurrent conflicts arise. We present a key constraint structure, an LM pair; which may make up a local minimum, clarifying the mechanism of how conflicted coloring in an LM pair hinders stepwise refinement of hill-climbing. Experimental results show that LM pairs are strongly correlated with the search efficiency of the stochastic search algorithm.

This paper proposes a novel method that enables automatic modeling of virtual cities. The method makes use of L-systems to generate road networks and the genetic algorithm (GA) to generate building layouts. The road networks are composed of two types of roads-linear flow systems which are generated by using the Tree L-system and cellular networks which are generated by using the Map L-system. A generation procedure for road networks and building layouts is described. Some experimental results of generated road networks and virtual cities are also shown.

A system that reconstructs 3D models with algebraic curved surfaces from three orthographic views is described. In this paper, we present two features. First, we can directly reconstruct 3D models with algebraic curved surfaces without using a method of polyhedron approximation by introducing two kinds of supplementary lines: silhouette lines and tangency lines. Second, we develop new rules and heuristics to handle curved surfaces, used in combinatorial search of faces. Rules work to reduce the processing time, and heuristics are aiming at simulation of the way human interprets the three orthographic views. Soundness and efficiency of the proposed method are also proved experimentally.

A system that reconstructs 3D models from hand-drawn three-view drawings represented by binary images is described. The authors lay main stress on the description of a heuristics directed reconstruction algorithm. The proposed algorithm performs a combinatorial search based on the face decision strategy along with two heuristics aiming at simulating the human's understanding way of interpretation. One is for finding a good sequence of search nodes, and the other for finding more natural scenes earlier than unusual ones.>

Binary search method is a well-known and a fundamental technique to search a key out of an ordered table. Fibonacci serh is kind of binary search adopting nonequal splitting criterion for dividing the remaining part of the table. This paper clarifies another advantage of Fibonacci search, which has not been found so far. First, it is shown that, from the viewpoint of the amount of head movement, Fibonacci search gives more than 10 percent better efficiency than the ordinary binary search. Furthermore, we propose a novel variation of Fibonacci search, and show that it attains nearly 20 percent better efficiency in average than the ordinary binary search.