bluuebunny/crossref_metadata_2025_split huggingface dataset:
Generation and forward displacement analysis of two new classes of analytic 6‐SPS parallel manipulators
Authors: Kong Xianwen , Gosselin Clément M. 
Published: August 2002

AbstractAnalytic manipulators are manipulators with a characteristic polynomial of fourth degree or lower. Using the component approach to generate analytic 6‐SPS parallel manipulators (PMs), the generation process is reduced to the generation of analytic components for 6‐SPS PMs. Two new classes of analytic components for 6‐SPS PMs are generated at first. Then, two new classes, IX and X, of analytic 6‐SPS PMs are generated. The forward displacement analysis (FDA) of the new analytic 6‐SPS PMs is also performed. The FDA of the 6‐SPS PMs of class IX is reduced to the solution of one univariate cubic equation and two univariate quadratic equations, in sequence, while that of the 6‐SPS PMs of class X is reduced to the solution of three univariate quadratic equations in sequence. Both of the new analytic 6‐SPS PMs have at most eight assembly modes. © 2001 John Wiley & Sons, Inc.
Fault detection and isolation in robotic manipulators via neural networks: A comparison among three architectures for residual analysis
Authors: Terra Marco Henrique , Tinós Renato 
Published: August 2002

AbstractIn this article we discuss artificial neural networks‐based fault detection and isolation (FDI) applications for robotic manipulators. The artificial neural networks (ANNs) are used for both residual generation and residual analysis. A multilayer perceptron (MLP) is employed to reproduce the dynamics of the robotic manipulator. Its outputs are compared with actual position and velocity measurements, generating the so‐called residual vector. The residuals, when properly analyzed, provides an indication of the status of the robot (normal or faulty operation). Three ANNs architectures are employed in the residual analysis. The first is a radial basis function network (RBFN) which uses the residuals of position and velocity to perform fault identification. The second is again an RBFN, except that it uses only the velocity residuals. The third is an MLP which also performs fault identification utilizing only the velocity residuals. The MLP is trained with the classical back‐propagation algorithm and the RBFN is trained with a Kohonen self‐organizing map (KSOM). We validate the concepts discussed in a thorough simulation study of a Puma 560 and with experimental results with a 3‐joint planar manipulator. © 2001 John Wiley & Sons, Inc.
Causal approximate inversion for control of structurally flexible manipulators using nonlinear inner–outer factorization
Authors: Cree A. G. , Damaren C. J. 
Published: August 2002

AbstractA control scheme for flexible‐link manipulators is advanced which is based on the notion of nonlinear inner–outer factorization. It is well known that the inverse of the forward dynamics map from joint torques to manipulator tip motion is noncausal and cannot be implemented in conjunction with real‐time path planning. The methods used here determine causal approximations for the inverse dynamics using the inverse of the outer (stable and minimum phase) factor and a static approximation for the inverse of the inner (lossless but nonminimum phase) factor. The Hamilton–Jacobi equation that arises is approximated by a state‐dependent Riccati equation at each time step. The factorization procedure yields the corresponding joint trajectories which can serve as reference trajectories for closing joint‐based feedback loops. Experimental results from a planar three‐link manipulator with two flexible links demonstrate the efficacy of the procedure. © 2001 John Wiley & Sons, Inc.
A further result of the nonlinear mixedH2/H∞tracking control problem for robotic systems
Authors: Huang C. Q. , Wang X. G. , Wang Z. G. 
Published: August 2002

AbstractThe design objective of a mixedH2/H∞control is to find theH2optimal tracking control law under a prescribed disturbance attenuation level. With the help of the technique of completing the squares, a further result of the mixedH2/H∞optimal tracking control problem is presented, by combining it with standard LQ optimal control technique. In this paper, only a nonlinear time‐varying Riccati equation is required to solve the problem in the design procedure—instead of two coupled nonlinear time‐varying Riccati equations, or two coupled linear algebraic Riccati‐Iike equations—with some assumptions made regarding the weighting matrices in the existing results. A closed‐form controller for the mixedH2/H∞robotic tracking problem is simply constructed with a matrix inequality check. Moreover, it shows that the existing results are the special cases of these results. Finally, detailed comparison is performed by numerical simulation of a two‐link robotic manipulator. © 2002 John Wiley & Sons, Inc.
On the optimality of the random hyperplane rounding technique for MAX CUT
Authors: Feige Uriel , Schechtman Gideon 
Published: August 2002

AbstractMAX CUT is the problem of partitioning the vertices of a graph into two sets, maximizing the number of edges joining these sets. This problem is NP‐hard. Goemans and Williamson proposed an algorithm that first uses a semidefinite programming relaxation of MAX CUT to embed the vertices of the graph on the surface of ann‐dimensional sphere, and then uses a random hyperplane to cut the sphere in two, giving a cut of the graph. They show that the expected number of edges in the random cut is at least α · sdp, where α ≃ 0.87856 and sdp is the value of the semidefinite program, which is an upper bound on opt, the number of edges in the maximum cut. This manuscript shows the following results: (1) The integrality ratio of the semidefinite program is α. The previously known bound on the integrality ratio was roughly 0.8845. (2) In the presence of the so‐called “triangle constraints,” the integrality ratio is no better than roughly 0.891. The previously known bound was above 0.95. (3) There are graphs and optimal embeddings for which thebesthyperplane approximates opt within a ratio no better than α, even in the presence of additional valid constraints. This strengthens a result of Karloff that applied only to the expected number of edges cut by a random hyperplane. © 2002 Wiley Periodicals, Inc. Random Struct. Alg., 20: 403–440, 2002
The ζ(2) limit in the random assignment problem
Authors: Aldous David J. 
Published: August 2002

AbstractThe random assignment (or bipartite matching) problem asks about An=minπ ∑c(i, π(i)), where (c(i, j)) is a n×n matrix with i.i.d. entries, say with exponential(1) distribution, and the minimum is over permutations π. Mézard and Parisi (1987) used the replica method from statistical physics to argue nonrigorously that EAn→ζ(2)=π2/6. Aldous (1992) identified the limit in terms of a matching problem on a limit infinite tree. Here we construct the optimal matching on the infinite tree. This yields a rigorous proof of the ζ(2) limit and of the conjectured limit distribution of edge‐costs and their rank‐orders in the optimal matching. It also yields the asymptotic essential uniqueness property: every almost‐optimal matching coincides with the optimal matching except on a small proportion of edges. ©2001 John Wiley & Sons, Inc. Random Struct. Alg., 18: 381–418, 2001
TCP modifications over satellite channels: study and performance evaluation
Authors: Marchese Mario 
Published: August 2002

AbstractThe paper presents a study and an analysis of the performance offered by TCP over a GEO (geostationary orbit) satellite link. The characteristics of satellite channels (notably the large round trip delay) heavily influence the TCP flow control, which is essentially based on acknowledgements. The effect is a delay in the acknowledgement reception and, consequently, in the delivery of messages, with respect to cabled networks. The drawbacks of using TCP in a satellite environment may be mitigated by a proper tuning of some TCP parameters. The behaviour of the protocol, as a consequence of variations in the buffer length of both transmitter and receiver and in the initial congestion window, is investigated in the paper and a proper configuration that drastically improves performance (measured by the throughput in bytes/s and by the overall transmission time) is proposed. Two test environments have been used to evaluate the proposed modifications: a real testbed, composed of two remote hosts connected through a satellite channel, and a satellite network emulator, composed of three PCs (two of them representing two hosts, the third one reproducing the behaviour of the satellite link). In both environments, a ftp‐like application designed for the aim has represented the reference application; three different file sizes have been used and the different effect of the tuning, depending on the transfer length, has been evidenced; the analysis includes both the single application case and the multiple application case, where several connections a time share the satellite link. Copyright © 2001 John Wiley & Sons, Ltd.
First year chemical engineering students' conceptions of energy in solution processes: Phenomenographic categories for common knowledge construction
Authors: Ebenezer Jazlin V. , Fraser Duncan M. 
Published: August 2002

AbstractIn this article, we examine first‐year chemical engineering students' conceptions of the energy changes taking place in dissolution. Students were individually interviewed with three tasks in which three different salts were dissolved in water, and 17 transcripts were analyzed using a phenomenographic methodology. Four descriptive categories of energy in dissolution were discerned: (a) you give energy (n= 1); (b) water gives energy (n= 17); (c) salt gives off energy (n= 13); and (d) reaction gives off energy (n= 7). Four students gave the same explanation for all three tasks, but more students used the same explanation for two of the tasks: four for Tasks A and B, four for Tasks B and C, and eight for Tasks A and C. Moreover, “salt gives off energy” was the most common explanation for Tasks A and B (n= 3), “reaction gives off energy” for Tasks B and C (n= 3), and “water gives energy” for Tasks A and C (n= 8). Four of the students showed variations of conception within tasks. Students described the solution process of all three tasks using a range of concepts, including previously learned chemical concepts. Even where students used the same chemical concepts in each of the tasks, they did not always give the same meaning to the concepts they used. The phenomenographic categories explanations given by students were used as a basis for developing an approach to teaching energy in solution processes. It is argued that this approach of using phenomenographic categories described at a collective level as a basis for discourse for constructing common knowledge should be used in teaching. It is proposed that a future study must be conducted to develop new trajectories students take to arrive at common knowledge and to understand how to move learners from their personal conceptions to plausible models in solution chemistry within the classroom learning community. Implications for policy are also discussed. © 2001 John Wiley & Sons, Inc.Sci Ed85:509–535, 2001.
The future of Lisp
Authors: Takeuchi Ikuo 
Published: August 2002

AbstractLisp has taken root widely and deeply in various fields, despite the decline of the AI fever in the 1980s and the common belief that Lisp has long been only a laboratory programming language. In the age of heterogeneous parallel computing, certain languages will survive and consolidate their positions. Lisp is surely classified among these languages. Moreover, Lisp has the potential to be a good system programming language, even suitable for writing an operating system, if real‐time garbage collection technology is further matured. © 2002 Wiley Periodicals, Inc. Syst Comp Jpn, 33(6): 10–18, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/scj.10000
Vision system for object handling robot using a low‐resolution range image and an intensity image
Authors: Hashimoto Manabu , Haga Tetsuji , Sumi Kazuhiko 
Published: August 2002

AbstractIn this paper, we propose an object recognition system which consists of two modules. One is an object extraction module using a low‐resolution range image. The other is a position measurement module for detecting precise position of each object using an intensity edge image. To acquire a range image, we propose stereo vision with random‐dot pattern projection. This method enables reliable stereo matching, even if there is no texture on the objects. The equipment is simple because a variable pattern is not necessary. We found this system has 99.8% recognition reliability and the processing time is approximately 5 s/image, providing satisfactory performance for practical use. © 2002 Wiley Periodicals, Inc. Syst Comp Jpn, 33(7): 21–29, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/scj.10055
An enhanced fault model for high defect coverage
Authors: Sang Junzhi , Shinogi Tsuyoshi , Takase Haruhiko , Kita Hidehiko , Hayashi Terumine 
Published: August 2002

AbstractIn this paper, we propose an enhanced fault model to increase coverage in detecting physical faults in LSI. First, as an alternative to the single stuck‐at fault model, we propose the “single gate logical fault with Hamming distance 1” (SGLFH1) model, which is capable of generating test pattern sets that detect more defects from the same number of faults. The characteristics of this fault model are discussed and the effectiveness of the test pattern sets generated by it is described. Next we show that the multiple detection test pattern set for single stuck‐at faults that is conventionally used to enhance defect coverage does not detect SGLFH1 faults satisfactorily. In addition, the effectiveness of the proposed model is shown by comparing the fault detection ratio of the SGLFH1 test pattern set for physical surrogate faults [1, 2] with the corresponding fault detection ratio of the multiple detection test pattern set for single stuck‐at faults. © 2001 Scripta Technica, Syst Comp Jpn, 32(6): 36–44, 2001
Analyzing social interactions in a mobile computing environment and application to agent communication service: Experiments under the ICMAS'96 mobile assistant project
Authors: Nishibe Yoshiyasu , Waki Hiroaki , Morihara Ichiro , Hattori Fumio 
Published: August 2002

AbstractExpectations for communication services in a mobile environment grow with the spread of portable computers and cellular telephones. However, knowledge of users' behavior in a mobile environment is necessary to judge the constraints imposed on users, and functions that agents must offer to users. The authors provided a variety of mobile services (not only conventional e‐mail but also information guides related to conference schedule, area, and so on) to more than 100 participants of an international conference through portable terminals and mobile telephones; in so doing, massive usage data were acquired. These usage data were compared to those of commercial services using the same terminals, and mobile computing usage proved to be clearly reflective of users' everyday activity patterns. The following facts that were revealed should be taken into account when designing information services under mobile environment. (1) A remarkable trade‐off exists between frequency of access to server, and size of data downloaded to terminals. (2) Impatient users are likely to cancel data acquisition, or to terminate communications. Proceeding from the obtained results, the following functions were shown to be necessary for agents in mobile environment: (1) distribution of information between server and terminals; (2) technological and psychological measures to encourage users to employ server connections. © 2001 Scripta Technica, Syst Comp Jpn, 32(7): 62–70, 2001
Very low bit rate speech coding based on HMMs
Authors: Hiroi Jun , Tokuda Keiichi , Masuko Takashi , Kobayashi Takao , Kitamura Tadashi 
Published: August 2002

AbstractIn this paper the authors describe very low bit rate speech coding based on HMMs (Hidden Markov Models). In the coder, phoneme recognition is performed using HMMs, then the phoneme index array, state duration length, and pitch information are sent to the decoder. In the decoder, the phoneme HMMs are linked in accordance with the phoneme index array. Then, a mel‐cepstral array is generated from the linked HMMs based on a speech parameter generation algorithm using likelihood maximization standards in accordance with the state duration length. Finally, speech is synthesized by exciting an MLSA (Mel Log Spectrum Approximation) filter with the generated mel‐cepstral as a coefficient in accordance with the pitch information. The results of subjective evaluation experiments show that performance similar to a vocoder based on 400 bit/s (8 bit/frame × 50 frame/s) vector quantization excluding pitch information can be obtained using the proposed format at 146 bits/s (including a 26% silent interval) excluding pitch information. © 2001 Scripta Technica, Syst Comp Jpn, 32(12): 38–46, 2001
Introducing the fisheye view into graph drawing algorithm
Authors: Nagumo Jun , Tanaka Jiro 
Published: August 2002

AbstractIn this paper, an algorithm is proposed for automatic drawing of undirected graphs. Specifically, a modified method of introducing a fisheye view into the force‐directed redrawing algorithm is offered. The proposed representation involves enlargement of regions located near specified nodes and contraction of far regions by varying the edge length while not using node position data, which ensures easy incorporation into the conventional force‐directed rearrangement technique. In addition, smooth display of graph transformations using the results of subsequent iterative calculation, which is a feature of the force‐directed algorithm, is maintained. © 2001 Scripta Technica, Syst Comp Jpn, 32(12): 60–66, 2001
Improvement of imaging speed in fluorescent x‐ray computed tomography using synchrotron radiation
Authors: Hasegawa Yasuhiro , Yu Quanwen , Noto Daisuke , Takeda Tohoru , Hyodo Kazuyuki , Yashiro Toru , Yuasa Tetsuya , Hiranaka Yukio , Itai Yuji , Akatsuka Takao 
Published: August 2002

AbstractImproving the speed of fluorescent X‐ray CT imaging using synchrotron radiation has been studied from the points of view of the imaging system and the processing algorithm. Regarding the imaging system, high‐speed imaging at 2 seconds per point with a dead time of about 6% has been realized by incorporating an electronic system which operates stably in the high count rate region. In addition, the amounts of computation and memory required have been reduced to about 1/100 of the levels realized up to now by improving the efficiency of the reconstruction algorithm. The quantitative properties of this system have been confirmed by tests with a physical phantom and the iodine distribution has been estimated in in vitro human thyroid images. These results indicate the implementability of in vivo fluorescent X‐ray CT instrumentation. © 2002 Scripta Technica, Syst Comp Jpn, 33(2): 1–11, 2002
A study on schema preservation by crossover
Authors: Yamamoto Kimihiro , Naito Shozo 
Published: August 2002

AbstractThis paper considers the combinatorial optimization problem in which the solution (sample) can be decomposed linearly into multiple schemata. Focusing on an arbitrary kind of schema, the schema preservation mechanism of the crossover in the genetic algorithm is discussed from the viewpoint of the increase or decrease of the number of samples (considered samples) containing the considered schema in the set of sample bit strings. It is shown that the change in the number of considered samples with time is divided into two kind of phases (stable and unstable phases), depending on whether or not there exists a point of equilibrium for increase and decrease in copying during the course of selection, and for degradation by destruction in crossover and mutation. It is shown that the transition between the stable phase and the unstable phase occurs according to the magnitude relation between the average fitness of the considered samples and the average fitness of the whole set of sample bit strings. By setting the crossover ratio as a higher value in the genetic algorithm, the schema is uniformly embedded in the whole set of sample bit strings, which increases the average fitness of the considered samples, and generates an equilibrium point that maintains a constant number of considered samples. Lastly, a computer simulation is performed, and it is shown that the discussion of the schema preservation mechanism of the crossover is adequate. © 2002 Scripta Technica, Syst Comp Jpn, 33(2): 64–76, 2002
A web page transmission mechanism with transmission order control of inline objects
Authors: Nakano Tadashi , Harumoto Kaname , Shimojo Shinji , Nishio Shojiro 
Published: August 2002

AbstractDue to the increasing popularity of the Internet, the WWW (World Wide Web) has become the most popular way to distribute multimedia contents. In the WWW, impressive information can be provided by embedding a large number of inline objects such as images in a WWW page. Since these inline objects are generally presented in WWW browsers in transmission order, the transmission order of inline objects becomes very important, especially for users accessing the Internet with a low‐speed connection such as a dial‐up line. In this paper, we propose a page transmission mechanism, which allows content authors to specify the transmission order of inline objects in WWW pages. First, we define a language to specify the transmission order of inline objects based on XML (Extensible Markup Language). We then discuss how we can implement the transmission order control, and propose a new protocol, HTSP (Hypertext Streaming Protocol), which realizes efficient transmission of ordered inline objects. © 2002 Wiley Periodicals, Inc. Syst Comp Jpn, 33(4): 14–24, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/scj.1116
Bookmark‐agent: Sharing of bookmarks for search assists
Authors: Mori Mikihiko , Yamada Seiji 
Published: August 2002

AbstractThe Bookmark‐Agent is a system which references bookmark files that register URLs which users are interested in, and then shares information among users. This engine can perform information searches more effectively than existing search engines. When a user is searching for a Web page by browsing, the agent searches for Web pages thought to represent what the user wants from among bookmarks, then presents a list in hyperlink form to the user's browser. In addition, the agent can also search other users' bookmarks by communicating with other users' agents. By using this agent in a small‐scale group consisting of users with similar interests, information which has been filtered by users, that is, bookmarks, can be used. As a result, the Bookmark‐Agent can display Web pages with a precision level higher than that of existing search engines. This is confirmed by experiments using six users for the purpose of evaluating the performance of the Bookmark‐Agent. © 2002 Wiley Periodicals, Inc. Syst Comp Jpn, 33(4): 69–76, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/scj.1121