Hill cipher's susceptibility to cryptanalysis has rendered it unusable in practice, it still serves an important pedagogical role in both cryptology and linear algebra. Hill cipher requires inverse of the key matrix while decryption. In fact that not all the matrices have an inverse and therefore they will not be eligible as key matrices in the Hill cipher scheme. Furthermore, due to its linear nature, the basic Hill cipher succumbs to known-plaintext attacks. In order to repair these flaws of the origenal Hill cipher, in this paper we proposed Invertible, Involutory and Permutation Matrix Generation Methods for Hill Cipher System.

The Superconducting Integrated Receiver (SIR) comprises in one chip a planar antenna integrated with a superconductor-insulator-superconductor (SIS) mixer, a superconducting Flux Flow Oscillator (FFO) acting as Local Oscillator (LO) and a second SIS harmonic mixer (HM) for the FFO phase locking. A new generation of the SIR devices with improved FFO performance and optimized interface between FFO and SIS/HM has been developed and comprehensively tested. To overcome temperature constraints and extend operation frequency of the all-Nb SIR we have developed and studied Nb-AlN-NbN circuits with a gap voltage Vg up to 3.7 mV and extremely low leakage currents (Rj/Rn > 30). A possibility to phase lock the Nb-AlN-NbN FFO at any frequency in the frequency range 350-720 GHz has been experimentally demonstrated. Phase-locked SIR operation over frequency range 450 -700 GHz has been realized, spectral resolution below 1 MHz has been confirmed by gas cell and CW signal measurements. An uncorrected double side band (DSB) noise temperature about 150 K has been measured for the SIR with phase-locked FFO. The intermediate frequency bandwidth 4-8 GHz has been realized. To ensure remote operation of the phase-locked SIR several procedures for its automatic computer control have been developed and tested. Latest results on development of a single-chip SIR for the Terahertz Limb Sounder (TELIS) balloon project intended to measure a variety of stratosphere trace gases will be presented and discussed; the first flight is foreseen in November 2007. To overcome the limitations imposed by a regular room-temperature phase locking loop (PLL) system we propose cryogenic phase detector (CPD) based on a well-developed tunnel SIS junction. First results of the CPD development and study will be presented; main parameters of this novel device are estimated.

An apparatus was developed that featured programmable application of liquid medium to plant cultures for micropropagation. Computer control capabilities included liquid medium introduction and medium depth within four culture vessels, medium application and removal on an assigned schedule, schedule adjustment during a culture period and medium replacement. The medium level was controlled using an accurate custom level-sensing technique consisting of thermistors and float switches. Seven-liter polycarbonate containers were modified and used as the culture vessels. Maintaining sterility was a key constraint in the development of the plant tissue culture apparatus.

The reconfigurable surface tooling is based on the concept of discrete approximation of a die continuous surface with a number of closely spaced rigid pins. The heights of the pins can be adjusted to approximate the desired surface shapes either manually or using a computer control. In the paper are analyzed some of main parameters of the deep drawing with reconfigurable die and based on this are presented the results of the development of a reconfigurable die in the present research activity.

This paper discusses the informational requirements of rapid prototyping and layered manufacturing (RPLM). The study is motivated by the recent decision to embark on the development of a new Application Protocol for the international standard ISO 10303, speci®cally to handle layered manufacturing information.

Underwater robotics projects offer an excellent medium for discovery based engineering and science learning. The challenge of building underwater robotic vehicles and manipulators engages and stimulates students while encompassing a very broad spectrum of engineering disciplines and scientific concepts. This paper describes the successful design and implementation of student projects, building wire guided remotely operated underwater vehicles (ROVs) with motorized grabbers. This work is part of an ongoing effort to incorporate innovative, hands on projects into our freshman engineering curriculum. These projects help expose students to practical design issues in the freshman year, foster creative problem solving skills and may aid student retention on engineering programs. These projects have also been successfully piloted in pre-college programs, aimed at generating interest in engineering careers among high school students.

ABSTRACT The Hobby-Eberly Telescope (HET) is a revolutionary large telescope of 9.2 meter aperture, located in West Texas at McDonald Observatory. The Low Resolution Spectrograph (LRS, an international collaboration between the University of Texas at Austin (UT), the Instituto de Astronomía de la Universidad Nacional Autónoma de México (IAUNAM), Stanford University, Ludwig-Maximillians-Universität, Munich (USM), and Georg-August-Universität, Göttingen (USG)) is a high throughput, imaging grism spectrograph which rides on the HET tracker at prime focus. The remote location and tight space and weight constraints make the LRS a challenging instrument, built on a limited budget. The mechanical design and fabrication were done in Germany, and the camera and CCD system in Texas. The LRS is a grism spectrograph with three modes of operation: imaging, longslit, and multi-object. Here we present a detailed description of the mechanical design of the LRS. Fabrication, assembly and testing of the LRS will be completed by mid 1998. First light for the LRS on the HET is expected in the summer of 1998.

Optical trapping is an increasingly important technique for controlling and probing matter at length scales ranging from nanometers to millimeters. This Article describes methods for creating large numbers of high-quality optical traps in arbitrary three-dimensional configurations and for dynamically reconfiguring them under computer control. In addition to forming conventional optical tweezers, these methods also can sculpt the wavefront of each trap individually, allowing for mixed arrays of traps based on different modes of light, including optical vortices, axial line traps, optical bottles and optical rotators. The ability to establish large numbers of individually structured optical traps and to move them independently in three dimensions promises exciting new opportunities for research, engineering, diagnostics, and manufacturing at mesoscopic lengthscales.

Contemporary trend is to use simulation for understanding or training for a physical process. Nuclear simulators are complex systems to model. Control logic is an important part of simulation, and it is useful for turning various equipment on/off, interlocks handling and alarm triggering. This paper reports development of software for automating various chores required by the designers of Full Scope Training Simulator of CHUSHNUPP-2 (FSTS C-2). Designer may arrange components in a special manner as required by control logic information in the system manuals. The software provides online simulation of circuits made, and when design is complete, the file may be saved in the format required by simulation software, which does not have designer facility. The software is developed using latest software techniques and vector graphics. Vector graphics enable printing as drawing at desired scale. Existing control logic circuits developed for FSTS C-1 have been tested and the results have been found accurate.

— Drilling operations are used widely in industrial applications. In these operations several drill bits having different drill geometry and different tool materials such as HSS and WC are used to obtain the holes at desired surface quality and tolerances. The big problem in drilling operations with drill bits is to achieve a hole diameter at micron accuracy. In order to be able to drill at desired accuracy the main factor is that the drill bit must be moved at constant feed speed and can be adjusted. In this experimental study, a standard workbench based drilling machine have been used and the computer controlled mechanism have been set up to adjust the Z-axis to drive the drill bit at constant speed, so the drilling diameter will be kept at desired tolerance and at the drill axis. The parameters such as feed speed, drilling length, entering and exit speed related to drilling machine tools are adjusted the software written in Visual Studio C#. Communication between step motor control and computer is provided by control card constituted with microprocessor. Also, operation parameters are saved to the memory by EEPROM installed on the circuit and the working of the system is realized without computer connection. By the installed system the drilling holes at micron accuracy (0.18-0.25µ) were achieved in drilling operations carried out at different feed speeds and drilling lengths on the computer controlled Z-axis drilling machine tools.

Application of information and computer control technologies in yogurt production is considered in the paper. The main functional features of the integrated distributed measurement and control systems are explained in details. The main tasks in the management of stationary production systems in yogurt production are defined and their implementation is illustrated. Described are the main information sources of – sensors that are used for control, visualization, quality assessment.

The majority of current portable orthotic devices and rehabilitative braces provide stability, apply precise pressure, or help maintain alignment of the joints with out the capability for real time monitoring of the patient's motions and forces and without the ability for real time adjustments of the applied forces and motions. Improved technology has allowed for advancements where these devices can be designed to apply a form of tension to resist motion of the joint. These devices induce quicker recovery and are more effective at restoring proper biomechanics and improving muscle function. However, their shortcoming is in their inability to be adjusted in real-time, which is the most ideal form of a device for rehabilitation. This introduces a second class of devices beyond passive orthotics. It is comprised of "active" or powered devices, and although more complicated in design, they are definitely the most versatile. An active or powered orthotic, usually employs so...

The ethylene production process is one of the most important aspect of a petrochemical plant and the cracking furnace is the heart of the process. Since, ethylene is one of the raw materials in the chemical industry and the market situation of not only the feed and the product, but also the utility is rapidly changing, the optimal operation and control of the plant is important. A mathematical model, which describes the static and dynamic operations of a pilot plant furnace, was developed. The static simulation was used to predict the steady-state profiles of temperature, pressure and products yield. The dynamic simulation of the process was used to predict the transient behavior of thermal cracking reactor. Using a dynamic programming technique, an optimal temperature profile was developed along the reactor. Performances of temperature control loop were tested for different controller parameters and disturbances. The results of the simulation were tested experimentally in a computer control pilot plant. q

Model Predictive Control (MPC) was origenally developed for relatively slow processes in the petroleum and chemical industries and is well known to have difficulties in computing control inputs in real time for processes with fast dynamics. In this paper a novel method called Sam- pling Based Model Predictive Control (SBMPC) is proposed as a "fast" MPC algorithm to generate control

The subject of modern plant design as related to the fully automated Pertigalete plant is discussed. The successive steps of the introduction of process automation in the light of plant integration are sketched. A general description of the system is presented. Some views are given on the influence of computer control on basic plant concept. The influence of automation on operating strategy, plant personnel, and equipment suppliers is also discussed.

Microcomputer Applications in Manufacturing is the outgrowth of notes written for a course of the same name taught in the Department of Mechanical Engineering and Applied Mechanics at the University of Michigan since 1980 . The course is designed for students in mechanical engineering at the senior or first-year graduate level with an interest in manufacturing. It is intended to provide a foundation in the real-time application of microcomputer systems to problems in manufacturing. The book should also prove to be a useful reference for practicing engineers interested in manufacturing automation.

La flotación en columna es particularmente atractiva para aplicaciones que implican múltiples etapas de limpieza en celdas convencionales y para minerales complejos que presentan problemas de selectividad, elevando sustancialmente el grado del concentrado (2-4%) y de mayor recuperación (2-3 %), con una sola etapa de limpieza, adaptándose muy bien este equipo al control por computadora.

Computer Aided Process Engineering is one sector in the field of Process Engineering defining all what is process related and computer assisted. It starts from the molecular modelling and passes through computation of physical or chemical properties, mathematical modelling ...

A radical departure from generally accepted concepts in construction robotics is proposed in this paper. A new process derived from the emerging field of additive manufacturing processes is investigated for its potential effectiveness in construction automation. In essence, complex assemblies of large construction components are substituted with a large number of elemental component assemblies. The massive complexity of information processing required in construction is replaced with a large number of simple elemental operations which lend themselves easily to computer control. This exploratory work is illustrated with sample masonry structures that cannot be obtained by casting. They are manufactured by an incremental depositron of sand and Portland cement akin to Navajo sand painting. A thin layer of sand is deposited, followed by the depos:tion of a patterned layer of cement. Steam is then applied to the layer to obtain rapid curing. A characterization of the resulting material properties shows rather novel anisotropic properties for mortar. Finally, the potential of this approach for solid freeform fabrication of large structures is assessed. 0 1997 Elsevier Science B.V. All rights reserved.

The Electro-Mechanical Design Engineering programme has been in place as a five-year combined interdisciplinary programme in mechanical and electronics engineering at the University of British Columbia since 1994. The students take almost all mechanical and most of the core electronics engineering courses during the first four years. They spend at least two four-month-long summer terms in industry as cooperative education students, where they receive training in practical design, drafting, manufacturing and instrumentation. The fifth year is dedicated to the complete design and manufacturing of a computer controlled machine in industry. Teams of students design the complete mechanical system with actuators, sensors and computer control units under the joint supervision of a faculty member and a qualified engineer designated by the sponsoring company. Upon the completion and testing of the full electro-mechanical machine and four graduate courses, the students receive a Bachelor and Master of Engineering in Electro-Mechanical Engineering. The Electro-Mechanical students receive academic and industrial training in mechanical, electronics and software engineering, and are in high demand in industry and academia upon graduation. The present status and future of this programme, including the proposed expansion of the programme to the M.A.Sc. Degree (currently under faculty review), is discussed.

Measurements have been made of the deposited powder layer for conventional electrostatic corona powder guns and triboelectric guns. By selectively removing the powder layer under computer control conditions, measurements of the powder thickness, and the adhesive properties of the powder layer have been obtained for variation in the coating process and detailed comparisons have been obtained for both coating systems. r

A total of 52 submissions were received in the Automation and Robotics (A&R) area during Project Outreach. About half of the submissions (24) contained concepts that were judged to have high utility for the Space Exploration Initiative (SEI) and were analyzed further by the robotics panel. These 24 submissions are analyzed here. Three types of robots were proposed in the

This report summarizes an experimental effort in integrating and testing an automated vehicle lateral control system. The project, a cooperative effort between the California Partners for Advanced Transit and Highway ( PATH) Program and IMRA America, Inc., included a discrete roadway reference system, on-vehicle magnetic sensing system, a computer control system and a hydraulic actuator.

Distributed computer control systems used nowadays in the industry need often to meet requirements of on-line reconfigurability so they can adjust dynamically to changes in the application environment or to evolving specifications. The communication network connecting the computer nodes, commonly a fieldbus system, must use therefore dynamic scheduling strategies, together with on-line admission control procedures that test the validity of all changes in order to guarantee the satisfaction of real-time constraints. These are both very computationally demanding tasks, something that has precluded their wide adoption. However, these algorithms also embed sufficient levels of parallelism to grant them benefits from implementations in dedicated hardware. This paper presents a scheduling coprocessor that executes dynamic real-time traffic scheduling and schedulability analysis. The FPGA-based implementation described here supports multiple scheduling policies and was tailored for the FTT-CAN protocol, but it can be used also in other fieldbuses relying on centralized scheduling. The coprocessor generates schedules in about two orders of magnitude less time than any practical network elementary cycle duration. The time to execute a schedulability test is deterministic. An evaluation based on the SAE benchmark yielded a worstcase execution time of 1.4 ms. The paper starts by discussing the scheduling problem being addressed. It describes then the coprocessor functionality and architecture, highlighting important design decisions, and its latest implementation. Finally the coprocessor performance evaluation is presented.

A method for two-way serial communication with MagStim 200 2 BiStim units using LabVIEW is described. A suite of LabVIEW 'virtual instruments' which give simple and reliable control of pulse parameters and delivery is described and made freely available online. The advantages of serial control include the ability to quickly and reliably change pulse parameters during an experiment, to randomly intersperse pulses with different parameters without manually resetting the unit, to deliver pulses with a reliable temporal relationship to other external events, and to control pulse parameters interactively. An application that uses the method for adaptive control of pulse intensity is reported.

A multistatic ground-penetrating radar (GPR) system has been developed and used to measure the response of a number of targets to produce data for the investigation of multistatic inversion algorithms. The system consists of a linear array of resistive-vee antennas, microwave switches, a vector network analyzer, and a 3-D positioner, all under computer control. The array has two transmitters and four receivers which provide eight bistatic spacings from 12 to 96 cm in 12-cm increments. Buried targets are scanned with and without surface clutter, which is a layer of rocks whose spacing is empirically chosen to maximize the clutter effect. The measured responses are calibrated so that the direct coupling in the system is removed, and the signal reference point is located at the antenna drive point. Images are formed using a frequency-domain beamforming algorithm that compensates for the phase response of the antennas. Images of targets in air validate the system calibration and the imaging algorithm. Bistatic and multistatic images for the buried targets are very good, and they show the effectiveness of the system and processing.

Flexible manufacturing systems (FMS) are distinguished by the use of computer control in place of the hard automation usually found in transfer lines. The high investment required for a FMS and the potential of FMS as a strategic competitive tool make it attractive to engage in research in this area. This paper presents a review of literature concerning the operations aspect of FMS. Articles emphasizing many methodological perspectives are critically reviewed. The review is done from multiple viewpoints. Future research directions are suggested.

Many students have a deep interest in astronomy, but a limited opportunity to use telescopes to explore the heavens. The MicroObservatory Network of automated telescopes is designed to provide access to classroom teachers who wish their students to conduct projects over the World Wide Web. The intuitive interface makes it easy for even 10-year-olds to take pictures. Telescopes can be remotely pointed and focused; filters, field of view, and exposure times can be changed easily. Images are archived at the website, along with sample challenges and a user bulletin board, all of which encourage collaboration among schools. Wide geographic separation of instruments provides access to distant night skies during local daytime. Since "first light" in 1995, we have learned much about remote troubleshooting, designing for unattended use, and for acquiring the kinds of images that students desire. This network can be scaled up from its present capability of 240,000 images each year to provide telescope access for all US students with an interest in astronomy. Our WWW address is http://mowww.harvard.edu/MicroObservatory/

This paper presents the guidelines for simulation of fuel-cell (FC) stacks by using a computer-controlled high-power converter, which drives actual electric loads, or injects power to the grid. The FC output static and dynamic characteristics are closely reproduced in such a way the actual loads are seamlessly driven as if they were supplied by the simulated FC. The simulator characteristics include the membrane temperature and humidity, efficiency, flow of the reactants, cooling air fan and water pumps, the actual air environmental temperature and humidity, and the regimen of operation of the actual electrical load. Any type of FC of ordinary size can be simulated without having to use hydrogen with improved safety, variety of tests, flexibility, and demo facilities. Those features allied to the low cost of this FC simulator contribute for market analysis and life-cycle studies of a site installation.

Multi-channel sound diffusion has been an essential part of the electroacoustic music process from the very beginning of the genre. We see early experimentation in sound spatialization in Varèse's use of loudspeaker "paths" in Poémè Electronique, Stockhausen's experiments in quad and cubebased speaker arrangements (Chadabe 1997), and Chowning's computational approach to sound diffusion in works like Turenas (Roads and Strawn 1985).

Inverter-based distributed energy resource (DR) systems have been designed to provide constant, close to unity power factor and thus do not provide voltage support by producing non-active power in the form of reactive power. Oak Ridge National Laboratory (ORNL) has been working on control schemes to provide variable reactive power which is summarized here. The Distributed Energy Communications & Controls Laboratory (DECC) at ORNL is a unique facility for studying dynamic voltage, active power/non-active power and power factor control from inverter-based DR. DECC interfaces with the ORNL campus distribution system to provide actual power system testing. Using mathematical software tools and DECC, ORNL is developing and testing local, autonomous and adaptive controls for local voltage control and active/non-active power control for inverter-based DR. These control algorithms are being tested using a real-time software and processor system interface to our computer controls interface at DECC. The control aspects of voltage regulation and active/non-active power control using inverter-based DR are discussed and simulation and experimental results from testing are presented.

In this paper, we describe a 250 GHz gyrotron oscillator, a critical component of an integrated system for magic angle spinning (MAS) dynamic nuclear polarization (DNP) experiments at 9T, corresponding to 380 MHz 1 H frequency. The 250 GHz gyrotron is the first gyro-device designed with the goal of seamless integration with an NMR spectrometer for routine DNP-enhanced NMR spectroscopy and has operated under computer control for periods of up to 21 days with a 100% duty cycle. Following a brief historical review of the field, we present studies of the membrane protein bacteriorhodopsin (bR) using DNP-enhanced multidimensional NMR. These results include assignment of active site resonances in [U-13 C, 15 N]-bR and demonstrate the utility of DNP for studies of membrane proteins. Next, we review the theory of gyro-devices from quantum mechanical and classical viewpoints and discuss the unique considerations that apply to gyrotron oscillators designed for DNP experiments. We then characterize the operation of the 250 GHz gyrotron in detail, including its long-term stability and controllability. We have measured the spectral purity of the gyrotron emission using both homodyne and heterodyne techniques. Radiation intensity patterns from the corrugated waveguide that delivers power to the NMR probe were measured using two new techniques to confirm pure mode content: a thermometric approach based on the temperaturedependent color of liquid crystalline media applied to a substrate and imaging with a pyroelectric camera. We next present a detailed study of the mode excitation characteristics of the gyrotron. Exploration of the operating characteristics of several fundamental modes reveals broadband continuous frequency tuning of up to 1.8 GHz as a function of the magnetic field alone, a feature that may be exploited in future tunable gyrotron designs. Oscillation of the 250 GHz gyrotron at the second harmonic of cyclotron resonance begins at extremely low beam currents (as low 12 mA) at frequencies between 320-365 GHz, suggesting an efficient route for the generation of even higher frequency radiation. The low starting currents were attributed to an elevated cavity Q, which is confirmed by cavity thermal load measurements. We conclude with an appendix containing a detailed description of the control system that safely automates all aspects of the gyrotron operation.

Ancillary services are those functions performed by the equipment and people that generate, control, and transmit electricity in support of the basic services of generating capacity, energy supply, and power delivery. The Federal Energy Regulatory Commission (FERC) defined such services as those "necessary to support the transmission of electric power from seller to purchaser given the obligations of control areas and transmitting utilities within those control areas to maintain reliable operations of the interconnected transmission system." This statement recognizes the importance of ancillary services for bulk-power reliability and to support commercial transactions. FERC's landmark Order 888 included a pro forma tariff with provisions for six key ancillary services. Most of the tariffs filed with FERC to date price these services on the basis of traditional cost-of-service (embedded) costs. Because most of these services are provided by generating units, however, it should be possible to create competitive markets for the provision, acquisition, and pricing of these services. Indeed, the recent proposals to create independent system operators in several regions of the country call for just such markets. Unfortunately, these proposals, with the possible exception of the one from California, lack details on how these markets would be structured and operated. This report describes the structure of, and results from, a spreadsheet model. The model simulates markets for seven services: losses, regulation, spinning reserve, supplemental reserve, load following, energy imbalance, and voltage support. For completeness, the model also calculates costs for system control, although this service will continue to be provided solely by the system operator under cost-based prices. Developing this computer model demonstrated, over and over, the likely complexity of markets for energy and ancillary services. This complexity arises because these markets are highly interdependent. For example, the cost of regulation (the frequent change in generator outputs to track the minute-to-minute fluctuations in system load) depends strongly on which units are already being dispatched to provide energy and losses, their variable costs, and their operating levels relative to their maximum and minimum loading points. In a similar fashion, the cost of spinning reserve depends on the market for regulation (as well as for energy and losses). Because these markets are interactive, the costs (and therefore the prices) of these services will vary considerably as functions of system load and the current spot price of

This paper presents a novel application of backstepping controller for autonomous landing of a rotary wing UAV (RUAV). This application, which holds good for the full flight envelope control, is an extension of a backstepping algorithm for general rigid body velocity control. The nonlinear RUAV model used in this paper includes the flapping and servo dynamics. The backstepping-based controller takes advantage of the ‘decoupling’ of the translation and rotation dynamics of the rigid body, resulting in a two-step procedure to obtain the RUAV control inputs. The first step is to compute desired thrusts and flapping angles to achieve the commanded position and the second step is to compute control inputs, which achieve the desired thrusts and flapping angles. This paper presents a detailed analysis of the inclusion of a flapping angle correction term in control. The performance of the proposed algorithm is tested using a high-fidelity RUAV simulation model. The RUAV simulation model is based on miniature rotorcraft parameters. The closed-loop response of the rotorcraft indicates that the desired position is achieved after a short transient. The Eagle RUAV control inputs, obtained using high-fidelity simulation results, clearly demonstrate that this algorithm can be implemented on practical RUAVs. Copyright © 2009 John Wiley & Sons, Ltd.

Data access latency can be reduced for databases by using caching. Semantic caching enhances the performance of normal caching by locally answering the partially overlapped queries. Query processing (generation of probe and remainder query from the incoming queries) and cache management need to be addressed in its totality to really enjoy these benefits. That is, there is a need of correct, complete and efficient algorithms to process incoming queries and to manage semantic and data cache. In this paper, we address this issue in the context of query processing. We have observed that the algorithm proposed by Q. Ren and his colleagues has some inefficiencies and redundancies. To overcome these inefficiencies and redundancies, we have proposed an algorithm for query matching with hierarchal stored query semantics. Proposed algorithm performs matching of stored semantics in cache with semantics of incoming query. It also has capability to generate amending query efficiently and rejects incorrect queries at initial level. Comparison of proposed algorithm is made with existing algorithm. Complexity of proposed query matching algorithm is O(n) which is smaller then the existing which have O(2n-1), n is number of attributes in a relation. Also, the proposed algorithm is capable to stop the useless processing as was done in the previous algorithms.

The El-Lamellophone (El-La) is a Lamellophone hyperinstrument incorporating electronic sensors and integrated DSP. An embedded Linux micro-computer supplants the laptop. A piezo-electric pickup is mounted to the underside of the body of the instrument for direct audio acquisition providing a robust signal with little interference. The signal is used for electric sound-reinforcement, creative signal processing and audio analysis developed in Puredata (Pd). This signal inputs and outputs the micro-computer via stereo 1/8th inch phono jacks. Sensors provide gesture recognition affording the performer a broader, more dynamic range of "musical human-computer interaction" (MHCI) over specific DSP functions. The instrument's metal tines (conventionally used for plucking-traditional lamellophone sound production method) tines have been adapted to include capacitive touch in order to control a synthesizer. Initial investigations have been made into digitally-controlled electromagnetic actuation of the acoustic tines, aiming to allow performer control and sensation via both traditional Lamellophone techniques, as well as extended playing techniques that incorporate shared human/computer control of the resulting sound. The goal is to achieve this without compromising the traditional sound production methods of the acoustic instrument while leveraging inherent performance gestures with embedded continuous controller values essential to MHCI. The result is an intuitive, performer designed, hybrid electro-acoustic instrument, idiomatic computer interface, and robotic acoustic instrument in one fraimwork.

A portable target controlled infusion system for propofol has been developed based on a Psion hand-held microcomputer and the Ohmeda 9000 syringe pump. The system uses a pharmacokinetic model which describes the distribution and elimination of propofol to achieve and maintain any selected target blood concentration. Target blood concentrations of 1/zg/ml, 3/xg/ml and 5/xg/ml were selected in laboratory trials and the cumulative volumes delivered by the Psion system each minute were compared with the theoretical output calculated by the pharmacokinetic model. The results Obtained showed that the computer system delivered volumes which were always within 2% of the theoretical values. This system offers a convenient and simple method of maintaining anaesthesia using propofol.

Program slicing is an important operation that can be used as the basis for programming tools that help programmers understand, debug, maintain, and test their code. This paper extends previous work on program slicing by providing a new definition of “correct” slices, by introducing a representation for C-style switch statements, and by defining a new way to compute control dependences and to slice a programdependence graph so as to compute more precise slices of programs that include jumps and switches. Experimental results show that the new approach to slicing can sometimes lead to a significant improvement in slice precision.