This paper presents an assistant database design system, ExpertDB, which is based on entity-relationship (ER) approach. The approach is to synthesize a normalized ER schema (which consists of entity set and relationsh...
ISBN:
(纸本)9780897913720
This paper presents an assistant database design system, ExpertDB, which is based on entity-relationship (ER) approach. The approach is to synthesize a normalized ER schema (which consists of entity set and relationship set expressions) from functional dependencies (FD). Using as input the set of attributes and FD's, we derive the minimal cover of FD's, partition and regroup FD's, and finally form the entities and relationship sets. In every aspect of these derivations, ExpertDB provides assistance to the user, which is usually the database administrator (DBA), in the database design. The resulting ER schema is then mapped to relational schema.
Herein, it is shown that by exploiting integral definitions of well known special functions, through generalizations and differentiations, broad classes of definite integrals can be solved in closed form or in terms o...
详细信息
We present a real-time robot motion planner that is fast and complete to a resolution. The technique is guaranteed to find a path if one exists at the resolution, and all paths returned are safe. The planner can handl...
ISBN:
(纸本)9780897913447
We present a real-time robot motion planner that is fast and complete to a resolution. The technique is guaranteed to find a path if one exists at the resolution, and all paths returned are safe. The planner can handle any polyhedral geometry of robot and obstacles, including disjoint and highly concave unions of *** planner uses standard graphics hardware to rasterize configuration space obstacles into a series of bitmap slices, and then uses dynamic programming to create a navigation function (a discrete vector-valued function) and to calculate paths in this rasterized space. The motion paths which the planner produces are minimal with respect to an L1 (Manhattan) distance metric that includes rotation as well as *** examples are shown illustrating the competence of the planner at generating planar rotational and translational plans for complex two and three dimensional robots. Dynamic motion sequences, including complicated and non-obvious backtracking solutions, can be executed in real time.
It is shown that Symbolic Computation provides excellent tools for solving quantum mechanical problems by perturbation theory. The method presented herein solves for both the eigenfunctions and eigenenergies as power ...
详细信息
It is shown that Symbolic Computation provides excellent tools for solving quantum mechanical problems by perturbation theory. The method presented herein solves for both the eigenfunctions and eigenenergies as power series in the order parameter where each coefficient of the perturbation series is obtained in closed form. The algorithms are expressed in the Maple symbolic computation system but can be implemented on other systems. This approach avoids the use of an infinite basis set and some of the complications of degenerate perturbation theory. It is general and can, in principle, be applied to many separable systems.
When we think of energy issues, we generally conjure up ideas of conflicts between producers and consumers. These translate into visions of grand ideological conflicts between the left and the right. Wildavsky and Ten...
When we think of energy issues, we generally conjure up ideas of conflicts between producers and consumers. These translate into visions of grand ideological conflicts between the left and the right. Wildavsky and Tennenbaum (1981) speak of battles between "preservationists" and "industrialists." Kalt (1981) argues that "[tihe domestic energy 'crisis' is, far more than anything else, a quarrel over income distribution." Ideological straight fights are marked by a single dimension of conflict. In particular, ideological politics, as opposed to religious or ethnic cleavages, suggests a battle between left and right--or, producers and consumers in the case of energy battles. When there are only two contestants, one is sure to win if the group decision is made by majority rule. Even in the United States Congress, where complex rules often frustrate coherent policy formation, strongly-held positions can prevail over obstructionists if they are determined enough. Yet, during the 1970s many attempts to form a "national energy policy" failed. In the 1980s Congress again stumbled in making natural gas policy as it defeated both decontrol and recontrol proposals.
We address the problem of assigning multiple copies of n independently developed versions of a program to a set of m(m > n) possibly heterogeneous processors to maximize system reliability. This problem is viewed a...
详细信息
A methodology for the rigorous management of service (performance) requirements on a computer system is introduced utilizing statistical theory. Random sampling techniques coupled with non-parametric probability inequ...
详细信息
Air cushion vehicles (ACVs) have operated successfully on commercial routes for about twenty years. The routes are normally quite short; the craft are equipped with radar and radio navigation aids and maintain continu...
详细信息
Air cushion vehicles (ACVs) have operated successfully on commercial routes for about twenty years. The routes are normally quite short; the craft are equipped with radar and radio navigation aids and maintain continuous contact with their terminals. Navigation of these craft, therefore, does not present any unusual difficulty. The introduction of air cushion vehicles into military service, however, can present a very different picture, especially when external navigation aids are not available and the craft must navigate by dead reckoning. This paper considers the problems involved when navigating a high-speed air cushion vehicle by dead reckoning in conditions of poor visibility. A method is presented to assess the ACV's navigational capability under these circumstances. A figure of merit is used to determine the sensitivity of factors which affect navigation such as the range of visibility, point-to-point distance, speed, turning radius and accuracy of onboard equipment. The method provides simplistic but adequate answers and can be used effectively to compare the-capability and cost of alternative navigation concepts.
We study monotonic and non-monotonic Logics of Knowledge, giving decision procedures and completeness results. In particular we develop a model theory for a non-monotonic Logic of Knowledge and show that it correspond...
详细信息
暂无评论