Bidirectional edges problem: Part I—A simple algorithm

The bidirectional edges problem is to find an edge-labeling of an undirected network,G=(V, E), with a source and a sink, such that an edge [u, v] E is labeled (u, v) or (v, u) (or both) depending on the existence of a (simple) path from the source to sink that visits the verticesu andv, in the orderu, v orv, u, respectively. We provide several algorithms for this problem in the current paper and the sequel. In this paper we show the relation between this problem and the classical two-vertex-disjoint-paths problem and then devise a simple algorithm with a time complexity ofO(|E|·|V|²). In the sequel we improve the time complexity toO(|E|·|V|). The main technique exploits aclever partition of the graph into a set of paths and bridges which are then analyzed recursively.The bidirectional edges problem arises naturally in the context of the simulation of an MOS transistor network, in which a transistor may operate as a unilateral or a bilateral device, depending on the voltages at its source and drain nodes. For efficient simulation, it is required to detect the set of transistors that may operate as bilateral devices. Also, sometimes it is intended to propagate information in one direction only, and propagation in the wrong direction (resulting in asneak path) can cause functional error. Our algorithms can be used to detect all the sneak paths.This research was supported in part by National Science Foundation Grants DMS-8703458 and CCR-9002819.     

Revising Z: Part I – logic and semantics

This is the first of two related papers. We introduce a simple specification logic Z _C comprising a logic and a semantics (in ZF set theory) within which the logic is sound. We then provide an interpretation for (a rational reconstruction of) the specification language Z within Z _C . As a result we obtain a sound logic for Z, including a basic schema calculus. Received March 1998 / Accepted in revised form April 1999     

Modeling, microfabrication and experiments of a free–free cantilever bistable micro mechanism supported with a diamond configuration

Bistable micro mechanisms are gaining great attention in MEMS applications. This paper presents the mechanical modeling and experimental characterization of a bistable torsion/cantilever micro latching mechanism for performing low power bistable relay applications. The bistable micro mechanism consists of two cantilevers which form symmetrical rocker levers. The free–free cantilever is suspended by a diamond skeleton which in turn is attached to a torsion cantilever. A permanent magnet is placed beside for holding the closed state with a permalloy soft magnetic circuit. The special diamond support is designed to enhance the stiffness of the overhang beams. In order to deduce the spring stiffness of system, a mechanical modeling of the leveraged torsion/cantilever system was performed by Castigliano’s theorem. Meanwhile, the magnetostatic latching force was also deduced by the Maxwell electromagnetism theory. Then the device has been prepared by a laminated copper sacrificial layer process. This process can facilitate the fabrication complexities of traditional magnetic device with coil structures. Finally, mechanical performance was characterized by an atomic force microscopy, combined with finite element simulation using ANSYS^™ package and analysis model as well. Two stable states of the micro mechanism were hold successfully with no power consumption by interferoscope profilometry of WYKO optical profiling system.     

Application of robotics in onshore oil and gas industry—A review Part I

With ever increasing global demand and depleting resources for fossil fuels, oil and gas industry is now positively looking for advanced robotic solutions to increase their productivity and safety. With time easy resources of the fossil fuels are shrinking and newly searched reservoirs, to feed supply demands of global consumption, are mostly located in extreme environmental conditions such as hot deserts, deep water and arctic zone etc. Production of the fossil fuels, in such inhospitable environmental conditions, poses difficult challenges to health, safety and environment (HSE). Tragic incidents like Exxon Valdez and Deepwater Horizon oil spills are examples of such challenges. Therefore, oil and gas industry has lot to learn from successful implementation of robotics and automation for dull, dirty and dangerous (3D) tasks of manufacturing industry. Most of the robotics technologies, currently used in the oil and gas industry, are mainly focused on inspection, maintenance and repair (IMR) of plant facilities with higher frequency and accuracy. Fundamental idea, involved in the automatization of these processes, is based on the principle of teleoperation with skilled operator. Automation of 3D tasks not only improves HSE standards but also lead to much needed economic efficiency by reducing production cycle, floor space and number of staff members required for continuous inspection and manipulation of plant facilities. Considering the risks involved in this industry usage of completely autonomous robots, first without achieving very high reliability, is still a far fetch choice. Therefore, semi-autonomous robots, where actions are performed by robots but cognitive decisions are still taken by skilled operator, is an excellent choice for this industry as a near future solution. In the onshore oil and gas industry robotic solutions are used both in upstream and downstream processes, such as site survey, drilling, production and transportation, mainly focused in the form of in-pipe inspection robots (IPIRs), tank inspection robots (TIRs), unmanned aerial vehicles (UAVs) and wireless sensor networks (WSNs) etc. This paper presents the state of art robotic solutions currently used in onshore oil and gas facilities.     

Analysis and optimal design of plates and shells under dynamic loads – I: finite element and sensitivity analysis

In this paper we consider the development, integration, and application of reliable and efficient computational tools for the geometry modeling, mesh generation, structural analysis, and sensitivity analysis of variable-thickness plates and free-form shells under dynamic loads. A flexible shape-definition tool for surface modeling using Coons patches is considered to represent the shape and the thickness distribution of the structure, followed by an automatic mesh generator for structured meshes on the shell surface. Nine-node quadrilateral Mindlin–Reissner shell elements degenerated from 3D elements and with an assumed strain field, the so-called Huang–Hinton elements, are used for the FE discretization of the structure. The Newmark direct integration algorithm is used for the time discretization of the dynamic equilibrium equations for both the structural analysis and the semi-analytical (SA) sensitivity analysis. Alternatively, the sensitivities are computed by using the global finite difference (FD) method. Several examples are considered. In a companion paper, the tools presented here are combined with mathematical programming algorithms to form a robust and reliable structural optimization process to achieve better dynamic performance on the shell designs.     

SADDLE: A computer-aided structural analysis and dynamic design language—Part I. design system

The SADDLE system is a tool for computer-aided optimal design of structural and mechanical systems. The system is divided into four parts—the preprocessor, the ‘analyzer’, the ‘synthesizer’, and the postprocessor. The structural model and the design data are generated by the preprocessor. The analyzer uses the finite-element method to compute deflections and stresses in the structure. The synthesizer solves the design problem that is cast into a nonlinear programming format. The postprocessor is used to examine the analysis and design results. Different parts of the system interact via a global database. This study presents the design system configuration. In a companion study, the data management part is presented in detail. The user-interface for design is examined first. The design problem formulation, in the nonlinear programming problem context, is presented. The use of utility libraries to achieve this objective with a minimum programming effort is also explained. The article concludes with two numerical examples that belong to two different classes of design problems—a minimum weight design problem and a min-max problem.     

Computer-aided optimal design of a polar-based template digitizer-NC contouring system—I. Synthesis and contouring error minimization

This paper presents the computer-aided optimal design of a template digitizer-NC contouring system which utilizes a set of polar coordinates. The system can operate both as a copying machine or as a numerical control (NC) machine. Part I of the paper describes the proposed system and its salient features. It also analyzes the contouring error due to the incremental approximation of the contour. This error is dependent on the relative location of the contour pole from the machine pole. An objective function relating the area error to the position of the contour is derived and an optimization procedure to minimize this error is outlined. Test results of an attempt to locate the poles of three test contours for minimum error are then presented.     

Sampled-data theory applied to the modelling and control analysis of compression ignition engines—Part I†

Proposals for the use of electronic speed governing of diesel engines used for driving alternators has led to a re-examination of the dynamic behaviour of the engine for control purposes. If maximum advantage to the plant performance is to be achieved from using more complex and expensive governing devices, then better models of individual components in the power system for simulation and control studies may be necessary. This paper describes an investigation performed to model the engine in terms of a discrete system. The frequency domain properties of the model (for various numbers of cylinders) are examined and compared with the model usually assumed, as well as with the frequency response of an actual engine. A companion paper will extend this work using 2-transform techniques.     

Then and now: how far have we come? Part I

The political, technological and economic forces of the turbulent '80s mandated changes in the way the American healthcare sector conducted the business of caring for people. In this first of a two-part series, Computers in Healthcare examines the evolution of healthcare computing in several key application areas. Part I will explore progress in laboratory, radiology, patient accounting, case mix and patient care systems.     

Maximum principle for the optimal control of an ablation-transpiration cooling system with free final time and phase constraints

This paper is concerned with an optimal control problem of an abhtion-transpiration cooling control system with Stefan-Signorini boundary condition. As the continuation of the authors＇previous paper, the Dubovits Rii-Milyutin fimctional approach is again adopted in investigation of the Pontryagin＇ s maximun principle of the system. The necessary optimality condition is presented for the problem with free final horizon and phase constraints.     

On Graphical Studies of PEN-IM Sets of Boolean Functions and their Minimizations. Part I†

The graphs of the sets of all penultimate implicants of certain types of Boolean functions are obtained in this part of the paper. Identification of different C.H. Boolean functions with their graphs are then made and terms are coined to designate these functions for the easy pattern recognition of their graphs. Finally formulae are deduced which give the number of prime implicants that must be present in any minimal cover of these functions.     

The communications decency Act and the karma of chaos — Part 1

When the FBI set about its nationwide investigation of online pornography, it landed its first prime catch in February 1996. John Delmarle pleaded guilty to transmitting sexually explicit pictures of children through America Online and drew a five-year prison term in New York Federal court.¹ Then in mid July, a Federal grand jury in San Jose, California charged 16 people in the United States and abroad with conspiracy to possess and distribute child pornography. The defendants were members of the ‘Orchid Club’, an online paedophilia club, which inducted its members by requiring accounts of their sexual experiences with children. In one instance, members chatted electronically as two of the men molested a 10-year-old girl. At least eight children were molested in connection with the club and although 13 members were arrested and charged, three others have not yet been identified and are known only by their computer aliases.²     

A system of processes related by cause and effect Part I. The model†

This paper develops a mathematical model for a system composed of product producing processes. The system is divided into subsets of processes called cycles. In each cycle the processes are linearly ordered and related by a cause and effect relationship where a change in any one process propagates from process to process throughout the entire cycle. This cause and effect relationship is a structure on processes of a cycle which asserts that each process of the cycle performs a step in a sequence of steps that finally load to the main product for which the cycle is identified. It is shown here that this model exhibits many of the empirical properties we would expect. It obeys a conservation law. Also in its state of equilibrium reserves are unchanged and it is neither efficient nor inefficient. There are also additional empirically expected phenomena which it exhibits. With this model the system is also shown to be able to insulate itself from environmental stimuli which could be regarded as a state of sleep or hibernation. Clearly such a model has application to many disciplines including biology, economics and ecology.     

A thermodynamic description and phase relationships of the FeCr system: Part I the BCC phase and the sigma phase

A generalized approach which was applied successfully to account for the magnetic contribution to the thermodynamic properties of FeNi is applied to FeCr. The predicted magnetic specific heats for two bcc alloys at x_Cr = 0.16 and 0.21 are in good agreement with the experimental data available in the literature. The magnetic Gihbs energy, enthalpy and entropy for the bcc phase are obtained accordingly. The nonmagnetic thermodynamic properties of the bcc phase are obtained primarily from thermochemical data as well as those for the sigma phase. The calculated stable and metastable equilibria involving the bcc and sigma phases are in reasonable agreement with data reported in the literature. The calculated metastable miscibility gap of the bcc phase is highly asymmetric and the calculated spinodals show unusual features.     

On the theory of flexible neural networks – Part I: a survey paper

Although flexible neural networks (FNNs) have been used more successfully than classical neural networks (CNNs) in many industrial applications, nothing is rigorously known about their properties. In fact they are not even well known to the systems and control community. In the first part of this paper, existing structures of and results on FNNs are surveyed. In the second part FNNs are examined in a theoretical framework. As a result, theoretical evidence is given for the superiority of FNNs over CNNs and further properties of the former are developed. More precisely, several fundamental properties of feedforward and recurrent FNNs are established. This includes the universal approximation capability, minimality, controllability, observability, and identifiability. In the broad sense, the results of this paper help that general use of FNNs in systems and control theory and applications be based on firm theoretical foundations. Theoretical analysis and synthesis of FNN-based systems thus become possible. The paper is concluded by a collection of topics for future work.     

The motion planning problem and exponential stabilisation of a heavy chain. Part I†

A model of a heavy chain system with a punctual load (tip mass) in the form of a system of partial differential equations is interpreted as an abstract semigroup system on a Hilbert state space. Our aim is to solve the output motion planning problem of the same nature as in the case of an unloaded heavy chain (Grabowski, P. (2003 Grabowski, P. 2003. Abstract Semigroup Model of Heavy Chain System with Application to a Motion Planning Problem. Proceedings of 9th IEEE International Conference: Methods and Models in Automation and Robotics. 25–28 August2003, Mi?dzyzdroje, Poland. pp.77–86. (IS1-2-3.PDF) [Google Scholar]), ‘Abstract Semigroup Model of Heavy Chain System with Application to a Motion Planning Problem’, in Proceedings of 9th IEEE International Conference: Methods and Models in Automation and Robotics, 25–28 August, Mi?dzyzdroje, Poland, pp. 77–86 (IS1-2-3.PDF)). In order to solve this problem we first analyse its well-posedness and some basic properties. Next, we solve the output motion planning problem using a substitute of the inverse of the input–output operator represented in terms of the Laplace transforms. A problem of exponential stabilisation is also formulated and solved using a stabiliser of the colocated type. The exponential stabilisation is proved using the method of Lyapunov functionals combined with some frequency-domain tools. The method of Lyapunov functionals can be replaced by the spectral or exact controllability approach as shown in the second part (Grabowski, P. (2008 Grabowski, P. 2008. ‘The Motion Planning Problem and Exponential Stabilisation of a Heavy Chain. Part II’. Opuscula Mathematica, 28: 481–505. (2008) (Special issue dedicated to the memory of Professor Andrzej Lasota) [Google Scholar]), ‘The Motion Planning Problem and Exponential Stabilisation of a Heavy Chain. Part II’, Opuscula Mathematica, 28 (2008 Grabowski, P. 2008. ‘The Motion Planning Problem and Exponential Stabilisation of a Heavy Chain. Part II’. Opuscula Mathematica, 28: 481–505. (2008) (Special issue dedicated to the memory of Professor Andrzej Lasota) [Google Scholar]) (Special issue dedicated to the memory of Professor Andrzej Lasota), 481–505) of the present article. A laboratory setup which allows verification of the results in practice is described in detail. Its dynamical model is used as an example to illustrate the theoretical results.     

Automatic Virtual Entity Simulation of Conceptual Design Results—Part Ⅰ:Symbolic Scheme Generation and Identification

The development of new products of high quality,low unit cost,and short lead time to market are the key elements required for any enterprise to obtain a competitive advantage.For shorting the lead time to market and improving the creativity and performances of the product,a rule-based conceptual design approach and a methodology to simulate the conceptual design results generated in conceptual design process in automatical virtual entity form are presented in this paper.This part of paper presents a rule-based conceptual design method for generating creative conceptual design schemes of mechanisms based on Yan's kinematic chain regeneration creative design method.The design rules are adopted to describe the design requirements of the functional characteristics,the connection relationships and topological characteristics among mechanisms.Through the graphs-based reasoning process,the conceptual design space is expanded extremely,and the potential creative conceptual design results are then dug out.By refining the design rules,the solution exploration problem is avioded,and the tendentious conceptual design schemes are generated.Since mechanical,electrical and hydraulic subsystems can be transformed into general mechansims,the conceptual design method presented in this paper can also be applied in the conceptual design problem of complex mechatronic systems.And then the method to identify conceptual design schemes is given.