8317522
A Web-Based Distributed Programming Environment
A Java-based system called the GeoJAVA System was introduced in [1]. This system allows a user to remotely compile his/her own C/C++ programs and execute them for visualization among a group of remote users. DISPE, which stands for DIStributed Programming Environment, expands on the GeoJAVA System by allowing the resulting executables to be run on systems other than the host on which they were compiled, thus making the system more versatile. DISPE uses Common Object Request Broker (CORBA) services to enable executables compiled on this system to invoke methods in libraries on remote sites in an architecturally heterogeneous environment. Not only does this allow users to compile and execute their programs remotely, but the maintenance and duplication of libraries is lowered since agents are used to search for symbols in libraries located remotely and to compile them with the user's source code. As long as there is an Internet connection between the hosts on which these libraries reside, the agents can search and compile with these libraries.
18326125
Finding Rectilinear Paths Among Obstacles in a Two-Layer Interconnection Model
Finding the best rectilinear path with respect to the bends and teh lengths of paths connecting two given points in the presence of rectilinear obstacles in a two-layer model is studied in this paper. In this model, rectilinear obstacles on each layer are specified separately, and the orientation of routing in each layer is fixed. An algorithm is presented to transform any problem instance in the two-layer model to one in a one-layer model, so that almost all algorithms for finding rectilinear paths among obstacles in the plane can be applied. The transformation algorithm runs in O(e log e) time where e is the number of edges on obstacles lying on both layers. A direct graph-theoretic approach to finding a shortest path in the two-layer model, which is easier to implement is also presented. The algorithm runs in O(e log2 e) time.
16325574
Finding an Approximate Minimum-Link Visibility Path Inside a Simple Polygon
37965905
Rectilinear Paths among Rectilinear Obstacles
Given a set of obstacles and two distinguished points in the plane the problem of finding a collision-free path subject to a certain optimization function is a fundamental problem that arises in many fields, such as motion planning in robotics, wire routing in VLSI and logistics in operations research. In this survey we emphasize its applications to VLSI design and limit ourselves to the rectilinear domain in which the goal path to be computed and the underlying obstacles are all rectilinearly oriented, i.e., the segments are either horizontal or vertical. We consider different routing environments, and various optimization criteria pertaining to VLSI design, and provide a survey of results that have been developed in the past, present current results and give open problems for future research.
34901507
A faster algorithm for rubber-band equivalent transformation for planar VLSI layouts
In this paper we consider the problem of transforming a single-layer topological routing of n two-terminal nets into a rubber-band equivalent using rectilinear wires in the presence of rectilinear circuit modules. Given a topological planar VLSI layout sketch with |F| features and |W| noncrossing wire segments connecting n two-terminal nets, we present an O(|F|/spl middot/|W|) time algorithm to do the vertex-disjoint rubber-band equivalent transformation of these n nets if it exists. The algorithm consists of two phases, computing a loose homotopy with four spokes matrices, and computing a vertex-disjoint rubber-band equivalent of the given homotopy, each phase taking O(|F|/spl middot/|W|) time and space. Both complexities are asymptotically optimal in the worst case. From the vertex-disjoint rubber-band equivalent of the given homotopy, one can obtain the detailed routing within the same time complexity. Experimental results are also presented.
10484740
Labeling Points on a Single Line
In this paper, we consider a map labeling problem where the points to be labeled are restricted on a line. It is known that the 1d-4P and the 1d-4S unit-square label placement problem and the Slope-4P unit-square label placement problem can both be solved in linear time and the Slope-4S unit-square label placement problem can be solved in quadratic time in Ref. [8]. We extend the result to the following label placement problem: Slope-4P fixed-height (width) label or elastic label placement problem and present a linear time algorithm for it provided that the input points are given sorted. We further show that if the points are not sorted, the label placement problems have a lower bound of Ω(n log n), where n is the input size, under the algebraic computation tree model. Optimization versions of these point labeling problems are also considered.
10244494
An Intelligent and Efficient Traitor Tracing for Ubiquitous Environments
Broadcast encryption has been applied to transmit digital information such as multimedia, software and paid TV programs on the open networks. One of key factors in the broadcast encryption is that only previously authorized users can access the digital information. If the broadcast message is sent, first of all, the privileged users will decode the session key by using his or her personal key, which the user got previously. The user will get the digital information through this session key. As shown above, the user will obtain messages or session keys using the keys transmitted from a broadcaster, which process requires effective ways for the broadcaster to generate and distribute keys. In addition, when a user wants to withdraw or sign up, an effective process to renew a key is required. It is also necessary to chase and check users’ malicious activities or attacking others. This paper presents a method called Traitor Tracing to solve all these problems. Traitor tracing can check attackers and trace them. It also utilizes a proactive scheme for each user to have effective and intelligence renewal cycle to generate keys.
728532
Performance and correctness of the ATM ABR rate control scheme
We study both the correctness and performance of the source/destination protocol of the available bit rate (ABR) service in asynchronous transfer mode (ATM) networks. Although the basic source/destination protocol for congestion management is relatively simple, the protocol specification has to cope with several "real-world" cases such as failures and delayed/lost feedback which may introduce complexity. Rigorous proofs of the correct functioning of the protocol based on a formal specification is necessary. We use a formal extended finite state machine (EFSM) model to show that the ABR source/destination protocol is free of live-locks, so that under all conditions both resource management (RM) and data cells will be transmitted. We also show that the network options of explicit forward congestion indication (EFCI) and explicit rate (ER) interoperate correctly. We use the understanding of the informal English description of the source/destination behavior and of our EFSM model to derive conditions that ensure that the source transmission rate is stable in the presence of delayed or lost feedback RM cells, especially under the operation of a source rule that requires the reduction of the source rate under these conditions. We arrive at bounds on the number of consecutive RM cell losses tolerated while the rate remains stable. We also provide a worst-case analysis of the delay in turning around RM cells at the destination station and the worst-case inter-departure time of forward RM cells from the source.
29667666
Building a distributed asynchronous control unit through automatic derivation of hierarchically decomposed AFSMs from a CDFG
Although there are several successful asynchronous logic synthesis tools, it is still unwieldy for designers to conceive and describe behaviors for a number of controllers constituting an asynchronous control unit of a target system manually. In this paper, building a distributed asynchronous control unit automatically through automatic derivation of hierarchically decomposed AFSMs from a CDFG is suggested. A resulting control unit consists of small asynchronous controllers and has complete separation of 'execution controllers' and 'execution order controllers'. This distributive feature leads to significant improvements in the aspects of area, performance and synthesis time of derived control circuits.
36921568
A Study on Key Distribution and ID Registration in the AAA System for Ubiquitous Multimedia Environments
Media environment has been rapidly changed these days. Internet provides multimedia environment and has become a part of our everyday life as a new advertisement media. Authentication methods typically involve an authentication server in the home network from the authentication server of the external network, and then the external network is notified with the authentication result in the home authentication server. This paper discusses and proposes a key distribution protocol that ca be used when the user moves the external network and to ensure secure communication with the external authentication server. As the proposed technology does not receive the reissue of authentication from the home authentication server in case moving between the external authentications servers, authentication server overload can be reduced and the home network can be made to issue the key using the registered password.
6355860
Network Protocol System Fingerprinting - A Formal Approach
Network protocol system fingerprinting has been recognized as an important issue and a major threat to network security. Prevalent works rely largely on human experiences and insight of the protocol system specifications and implementations. Such ad-hoc approaches are inadequate in dealing with large complex protocol systems. In this paper we propose a formal approach for automated protocol system fingerprinting analysis and experiment. Parameterized Extended Finite State Machine is used to model protocol systems, and four categories of fingerprinting problems are formally defined. We propose and analyze algorithms for both active and passive fingerprinting and present our experimental results on Internet protocols. Furthermore, we investigate protection techniques against malicious fingerprinting and discuss the feasibility of two defense schemes, based on the protocol and application scenarios.