International Journal of Software Engineering and Knowledge Engineering

Robotics research and development span over five decades but is still not pervasive in our daily lives. This paper attempts to explain why and reviews compliant motion which is a crucial capability required to make robots pervasive. Robotic tasks are analyzed and algorithms for control of compliant motion of manipulators are presented.

This paper presents the process of a motion control system design and implementation for a teleminulation system. The robotic manipulator/hand is a nonlinear system with coupled effects among the joints. By applying the frequency response method, the nonlinear system is modeled as decoupled linear ones, in which each joint is controlled independently. The experimental results show the feasibility of the modeling process. Based on the obtained transfer function of each joint, the digital PID controllers are designed. The motion control system for the telemanipulation system is then implemented using the software package MATLAB, Simulink, Real Time Workshop, xPC Target and a C/C₊₊ compiler, and the hardware I/O boards, amplifiers, etc. The presented developing procedure shows a convenient way to implement a real time robotic control system.

In this paper, the system design issues of the Propulsion and Control System of the ROV II are analyzed and addressed. The design concept, some of the upgraded features of the ROV II in comparison to ROV I and the unified pilot training and control system developed, will also be briefly discussed in this paper.

In this paper, Axiomatic Design (AD) theory was adopted for the design analysis of an underactuated Remotely Operated Vehicle (ROV) system and its subcomponents. The system design issues of the Propulsion and Control System of the ROV II are analyzed and addressed based on the Independence Axiom methodology. The top-level Functional Requirements (FRs) for the thruster design and configuration are identified and its corresponding Design Parameters (DPs) are also presented.

For mobile computing system such as wearable computer, one of the most critical hardware issues is the provision of electric power. Various different sources of power for wearable computer have been investigated; however, we are interested only in power that can be generated in-situ, such as human power. This paper describes a novel mean of multiple source human power generation for small wearable electronic devices, and then demonstrates the digital information transfer between wearable computing devices by using human skin as "antenna".

There are a wide range of peripheral devices in a mobile computing system, such as sensors and identification memory tags. As the amount of such devices increases in a mobile computing design, there is a need for these devices to communicate efficiently with the central processing unit. Also, it is highly desirable that these devices could be conveniently connected to the wearable computer without many dangling wires. We developed a personal area network (PAN) system which attempts to interconnect such devices, and at the same time uses human body as communication channel. This system is in a way novel because it is totally powered by human motion.

This paper presents the concept of implementing different dielectric properties of surroundings to monitor the sleep of eczema patients through the use of an electric field mattress. Different sensor methods, as well as different arrangements of electrodes in the E-field mattress, are discussed to find out which would achieve optimum results. This paper also explains how readings taken from the electrodes can be used to analyze the sleep pattern of eczema patients.

A smart shirt was developed for geriatric healthcare purposes. It can summon medical assistances via SMS and e-mail when its bearer has fallen. Single axis accelerometers are arranged in medio-lateral, vertical and antero-posterior direction on the shoulder part of the shirt. Using Bluetooth™ transmitter/receiver, signals are transmitted and processed on a Personal Computer (PC) for fall-detection. Upon detection of falls, SMS (Short Messaging Service) and e-mail are sent through GSM (Global System for Mobile Communication) network supported by a local telecommunication service provider. The primary advantage of our detection system compared to other researchers' systems is that fall notification can be sent to individuals and medical health care unit simultaneously to lead to a shortened interval of the arrival of assistance.

Microcontroller plays an important role in gearing up scientific applications for measurements, data acquisition and controls. With the advent of technology in microcontrollers, a new era in the form of microconverter is available at the user's doorstep. Benefited by the excellent features of Analog Devices' microconverter chip ADuC 842, an attempt has been made to develop a Lilliputian platform for scientific applications at National Chemical Laboratory (NCL), Pune. A real time system has been developed for measuring surface tension exerted by Langmuir films formed at air water interface. The films are compressed by smooth and precision barrier mechanism through DC motor in a controlled manner. I²C compatible EEPROM is provided on board for data storage and it can be communicated to a PC through RS232 link for further analysis. The other features provided are, In-circuit programming for firmware updating, keyboard functioning for special routine executions, I²C compatible RTC and battery backup. The software has been completely developed using assembly language programming. Intelligent Lilliputian platform designed using ADuC 842 chip and graphic LCD for real time plotting of surface pressure area isotherm of Langmuir films has been developed and tested successfully at NCL.

An embedded, real-time, loosely-coupled INS/GPS integration system has been developed and used for an unmanned land vehicle's control and navigation. For this integrated system, a Kalman filter software is used for INS error damping and corrections via the weighted aiding of a GPS output. The detailed development work will be presented in this paper including algorithm simplification, sensor selection and critical problems solving. Vehicular trial is also conducted. Simulated outage in GPS availability is made to assess the bridging accuracy of this system.

This paper describes the design and implementation of autonomous real-time motion recognition on a Personal Digital Assistant. All previous such applications have been non real-time and required user interaction. The motivation to use a PDA is to test the viability of performing complex video processing on an embedded platform. The application was constructed using a representation and recognition technique for identifying patterns using Hu Moments. The approach is based upon temporal templates (Motion Energy and History Images) and their matching in time. The implementation was done using Intel Integrated Performance Primitives functions in order to reduce the complexity of the application. Tests were conducted using 5 different motion actions like arm waving, walking from left and right of the camera, head tilting and bending forward. Suggestions were also made on how to improve the performance of the system and possible applications.

This paper presents the development of a three-channel telemetry system using Microchip rfPIC12F675 as transmitter and using rfRXD0420 as receiver. The highly integrated radio frequency IC chip features the system which is simple in structure, compact in size and low in power consumption. Using 3V power supply for the transmitter, the system is able to transmit low amplitude signal from 8 m to more than 50 m with power consumption as low as 10 mW. The biotelemetry system can be used in human or animal bio-signal acquisition and monitoring.

In the module integration process, lower level packaging elements such as devices, sub-mounts and components are combined as a functional block. Embedded sub-system consists of modules whose operations are controlled by a specific algorithm. Typically, the control algorithm is realized in a form of system software in a processor unit, which controls individual module operations and combines separate module operations as a system operation. In the creation of a cost-efficient embedded system it is essential that reliable, reproducible and cost-efficient building blocks of systems, modules, can be manufactured. We have studied Low Temperature Co-fired Ceramics (LTCC) substrate technology and its possibilities to produce reliable, reproducible and cost-efficient photonic and millimeter wave modules.

In this paper we introduce our contribution to the development of LTCC photonic and millimeter wave modules. Most of the papers written on LTCC packaging are in the field of RF and millimeter wave modules and are shortly reviewed in this paper. Photonic modules utilizing LTCC substrates are almost missing in the literature. Several photonic modules based on the use of LTCC substrates developed by our group are introduced in this paper, including hermetic fiber pigtailed power laser, wavelength tunable laser and 10 GBit/s/ch optical interconnects board for photonic applications. In addition, front-end module for 24 GHz transceiver for millimeter wave applications is introduced.

In this work, a new MEMS accelerometer with large detectable range of more than 50 g is designed. Three types of flexure designs were studied: the conventional straight flexure, newly proposed interlapped-L flexure and rectangular flexure. Their dimensions were optimized to achieve the desired requirements of the accelerometer. Capacitive sensing method and electrostatic actuation are selected to be the sensing and actuation methods. Governing equations derived from this model are used to compare with that of a second order spring-mass-damper system. These mathematical models are then used to formulate the various types of sensitivities. Finite Element Analysis software ANSYS is used in the design stage to simulate its dynamic behavior. The accelerometers with interlapped-L flexure and rectangular flexure present very large detectable range of 60 g and 80 g, sensitivity of 23.1 and 17.3 fF/g, with the noise floor of 17.9 and 18.2 μg/(Hz)^1/2 in atmosphere.

This paper presents a novel dielectrophoresis (DEP) device where the DEP electrodes define the channel walls. This is achieved by fabricating microfluidic channel walls from highly doped silicon so that they can also function as DEP electrodes. Compared with planar electrodes, this device increases the exhibited dielectrophoretic force on the particle, therefore decreases the applied potential and reduces the heating of the solution. A DEP device with triangle electrodes has been designed and fabricated. Compared with the other two configurations, semi-circular and square, triangle electrode presents an increased force, which can decrease the applied voltage and reduce the Joule effect. Yeast cells have been used to for testing the performance of the device.

Thermoelectric cooling system can be used in many applications. The properties of structured point contact at the cold end affect the performance of thermoelectric cooling. The performance of metal point junctions as a function of tip radius show that the smaller the tip radius, the better the figure of merit. This paper presents the modeling and analysis of the nanotips. Each nanotip will have to carry some fraction of the weight of the thermoelectric material and the silicon slabs. The small apical area of each nanotip causes a very high pressure build up. The device may be loaded externally to ensure proper nanotip and thermoelectric material contact. A deformation of approximately 10 to 15 nm would be ideal. Finite Element Analysis (FEA) needed to be applied to determine how tall each nanotip must be to maximize soft and hard tip contacts. FEA was also needed to approximate the amount of external loading that will be necessary. ANSYS software was used in the modeling and analysis of the nanotips.

The model of transient axially symmetric wave propagation in a circular elastic bar is studied by using the elastic wave propagation theory and the methods of integral transform. The numerical results of the model of longitudinal impact wave velocity are shown using a method of numerical analysis. This theoretical formula and methods of analysis is used in an experimental system to measure the dynamic characteristic of microstructure. Curves of the wave peak emulation of Davies bar are obtained by using theoretical formulation.

This paper presents a simplified model of 2D torsional micromirror for control design. The micromirror system is modeled as a two inputs two outputs (TITO) system with nonlinear electrostatic torques, which are coupled with the two inputs and the two tilt angles. The coupling property of the electrostatic torques makes it difficult to design the control law. To surmount the problem, a new model based on extracting the dominant nonlinear terms and Taylor's expansion is proposed. The micromirror system together with the simplified model is coded in Matlab™ S-function. The simulation result shows that the model is feasible for control design.

In networked and distributed environments, and in multi-tasking systems, processes run simultaneously and compete to access the system resources. Processes commonly communicate with one another. Various techniques have been adapted in designing Interprocess Communication mechanisms within operating systems such as signals and message-passing. Signals are software interrupts notifying a process that an event has occurred; they do not support data exchange between processes. Message-Passing, a widely used technique in this design, it may use pipes to allow two or more processes to exchange data. Current techniques degrade performance of Real-time Systems, where unmet time critical missions may result in catastrophic failure. This research introduces a library-based architecture for Interprocess Communication Systems (IPC). This technique supports real-time performance and can be adapted for embedded operating systems. Improved Real-time performance was achieved by running IPC as a set of library function and verified by testing on real-time embedded system.

With low-power consumption, small code and data size, evolvability as design criteria, we develop an evolvable operating system (EOS) for wireless sensor network applications. The EOS provides memory space efficient thread management, collaborative thread communication model and network stack. It also supports power management of microcontroller and radio transceiver, and network wide time synchronization function. Above all, the most important feature is the concept of evolvability with which the operating system itself can be easily configurable and upgradeable.

The capability of seamlessly switching between two communication protocols will be very important for communication devices of the future, since it allows the end users to judiciously use whichever network is appropriate, depending on cost, signal strength or other factors such as the amount of battery life left on the device. This paper presents the groundbreaking idea of a Seamless Protocol Switching Layer (SPSL) on a hardware and software level to solve this problem. In addition, the SPSL concept is implemented by developing a prototype application, a Smart Video Phone, built using Intel XScale-based PXA255 board and ARM Linux as the operating system that can seamlessly switch between IEEE 802.11 and Bluetooth technologies. Experiments show that if the signal of the Bluetooth signal goes below 40%, the switching to Wireless-Fidelity (Wi-Fi) happens if it is available.

Tele-medical systems have proven to be very useful to improve patient outcomes. However, they suffered from drawbacks such as insufficient functionality, prohibitive cost, the lack of connectivity and many other factors. To solve these problems, medical experts were consulted and an embedded tele-medical system was developed that allows a doctor to analyze and predict the ailment of a patient and direct the paramedic on the scene to perform potentially life-saving corrective actions or even promote recovery. The system would capture, process and interpret ECG data from the patient using the low cost hardware which was designed.

Hybrid systems are ideal models of real control systems where the discrete controller interacts with the continuous system on a closed loop via A/D converters and digitally controlled actuators. We extend the notion of a predictive controller to hybrid systems by introducing the notion of predictive traces, the set of all possible traces of a hybrid system starting in some state and mode into the future. A control algorithm is developed that explores this set of predictive traces to determine the next control action.

HyPA is an algebraic theory based on the classical process algebra Algebra of Communicating Processes (ACP) for the specification and analysis of hybrid systems. We have the idea that HyPA is also well suited for addressing various aspects of digital embedded systems including hardware, software and concurrency, as well as mixed-signal designs. To show that HyPA is useful for the specification and analysis of hybrid systems and that our idea is correct, we illustrate the use of HyPA with some case studies: a point-to-point communication , a thermostat, a positive-edge-triggered D flip flop, and a small part of a mixed-signal fuzzy controller.

This contribution proposes a link between the specification of supervisory controllers by Sequential Function Charts (SFC) and the verification of embedded systems with hybrid dynamics. The SFC are transformed into modular timed automata using a procedure based on graph grammars. The resulting controller model is composed with a hybrid automaton (with possibly nonlinear continuous dynamics) that models the plant behavior. In order to verify safety properties of the composed system algorithmically, a tool implementing the recently proposed approach of counterexample guided model checking is employed. The procedure is illustrated for a processing system example.

This paper presents the development of a digital signal processor (DSP) based motion controller for a linear servo motor system. The linear motor system employs a moving magnet non-commutated DC linear servo motor as the actuator, and a linear variable differential transformer (LVDT) as the position feedback transducer. It is ideal for short stroke, high accuracy and high speed closed loop servo applications. The controller hardware is based on a TI TMS320LF2407A DSP. The system architecture and motion control strategies are presented. An index motion is implemented using this system. The experimental results with discussions are also given.

A microcontroller-based control system is a direct outgrowth of the extensive advances in the Integrated Circuit design and microelectronic device processing technology. This has led to the development of new forms of technologies. This paper presents a technique of microcontroller based control system for controlling the lights of a room. Using the technique, according to the intensity of the sunlight in a room, the states of light of that room will change. Therefore we need to collect data or information from the environment using light sensors to control lights. The microcontroller collects the information from the atmosphere and changes the state of different lights. The analog data collected by the sensors are converted to digital form by an Analog to Digital Converter (ADC) and then fed to the microcontroller. The output data stream of the microcontroller is in digital form by which analog device lights will be controlled.

In this paper, the methods to rapidly deploy closed-loop control systems are presented. A flexible real-time embedded platform based on reconfigurable computing technologies is established, on which control blocks consisting of optimized control algorithms are set up. By employing control blocks, a set of tools aiming to shorten the development cycle of embedded control systems are developed. Compare to conventional ways, the tools give controller developers much faster ways to construct required controllers with higher flexibility.

As many embedded microprocessors are battery driven, low power design is becoming increasingly necessary. In this paper, we proposed hardware-software co-design architecture for low power arithmetic and logic units. By including multiple functional units with the same functions and different speeds, we provide instruction implementations at various power prices. Then, with an assembler level scheduler, we identify and create situations whereby the low-power slow functional units can be utilized. The overall performance is not compromised as no additional stalls are introduced. Simulations show 10%~35% power saving in typical addition operations.

In next generation video surveillance systems there is a trend towards embedded solutions. Digital signal processors (DSP) are often used to provide the necessary computing power. The limited resources impose significant challenges for software development. Resource constraints must be met while facing increasing application complexity and pressing time-to-market demands. Recent advances in synthesis tools for Simulink suggest a high-level approach to algorithm implementation for embedded DSP systems. The model-based visual development process of Simulink facilitates simulation as well as synthesis of target specific code. In this work the modeling and code generation capabilities of Simulink are evaluated with respect to video analysis algorithms. Different models of a motion detection algorithm are used to synthesize code. The generated code targeted at a Texas Instruments TMS320C6416 DSP is compared to a hand-optimized reference. Experiments show that an ad hoc approach to synthesize complex image processing algorithms hardly yields optimal code for DSPs. However, several optimizations can be applied to improve performance.

Technical systems that include complex physical dynamics as well as extensive discrete event control, require powerful modeling and simulation techniques. As the most adequate means for modeling hybrid physical systems, we advocate the use of object-oriented modeling languages such as Modelica. However, the discrete event models often require the use of dedicated graphical editors that cannot be defined appropriately using Modelica. The purpose of the DES/M modeling environment [10] is to provide such editors for different discrete event formalisms and to translate discrete event models automatically into Modelica components such that a discrete event controller can be integrated easily into Modelica models and simulated using standard Modelica software tools. This contribution presents the main concepts used for the representation of several discrete event formalisms in the Modelica language and discusses the class of discrete event formalisms that can be supported by the DES/M environment.

On general purpose computer architectures, the optimization of redundancy elimination almost always improves the cycle count. We argue that a specific consideration should be taken when applying this optimization to embedded architectures that feature multiply-add(MADD) instruction. This paper presents a redundancy elimination algorithm with MADD operation aware consideration. It produces optimized results for both code size and cycle count. The algorithm is integrated into KylinC compiler, a compiler for embedded systems developed at the University of Delaware. Experimental results demonstrate that the cycle counts of the benchmark programs are reduced on average 8% and the code sizes are reduced on average 5.27%.

Security issues within a networking environment are critical, as attacks or intrusions can come from many different sources. Firewalls are an effective tool used for intrusion detection and provide protection against attacks on a system or network. In the past, protection barriers for a local network have been provided using software solutions. Emerging multi-gigabit networking technology and the high uptake of gigabit Ethernet has rendered these solutions inefficient as it cannot cope with the high data rate. In this paper, a new approach using reconfigurable hardware such as Field Programmable Gate Arrays is proposed to provide the flexibility and performance required for a gigabit firewall. The solution is extendable, has low cost and is capable of scanning multiple protocols. The design approach will allow it to be easily ported over to another family of chips with no or minor modification.

The design of embedded and hybrid systems requires powerful mechanisms for modeling data, state, concurrency and real-time behaviour. The {first} part of this paper illustrates a powerful design notation Timed Communicating Object Z (TCOZ) that has both channel based and sensor/actuator based interfaces. We believe that TCOZ is well suited for presenting more complete and coherent design models for complex embedded and hybrid systems. However, the challenge is how to analyze and check these models with tools support. One effective approach is to project (transform) the design models into multiple domains, then to use existing specialized tools in those domains to perform the checking and analyzing tasks. The second part of this paper demonstrates one particular projection from TCOZ designs to Timed Automata (TA) models so that TA model checkers can be used to check time related properties.

Time and energy is expended in switching between power modes (e.g., active, hibernate, sleep, etc.). Powering off cache is one major reason for this. When there is a switch in the power-mode involving cache power-off, the system spends time and energy in filling the cache with new data (inherent cache misses). In our technique, before powering off the cache, we save its state in Embedded DRAM and bring it back when the previous power mode is restored. Our experiments have showed that in a majority of cases the cache contents are too valuable to be erased. By saving the contents we can reduce switching speed and energy. We present a heuristic to save the most relevant cache contents so that power and delay overheads are minimized. To measure the area overhead a synthesizable VHDL model was designed.

Simulink is widely used within the industry for simulation and model-driven development, and reactive behaviors are often modeled using an add-on called Stateflow. Argos is one of the synchronous languages that have been proposed for the specification, validation and implementation of reactive systems. It is a rigorously defined graphical notation which, though not as powerful as Stateflow, is much less complicated. This paper describes the implementation of an Argos block for Simulink.

The goal of this paper is to demonstrate the application of the algorithmic analysis of hybrid systems to idle speed control. This problem can be formulated as to design a safety hybrid controller. In principle, such controllers can be derived from the maximal invariant set. It is, however, hard to compute this set for a nonlinear hybrid system with both continuous control and disturbance inputs. We propose to use a class of piecewise constant control functions, which allows to develop an effective synthesis algorithm based on reachability computations. In addition, we show how assume-guarantee reasoning from automatic verification can be used to reduce the computational complexity.

Specification of embedded systems based on formal models of computation is gaining importance. The behavior of an increasing number of embedded systems is heterogeneous, consisting of a mixture of control-dominated and data-dominated parts. While models of computations suitable to control-dominated systems and data-dominated systems are well developed, there are only a limited number of models catering to both systems. In this paper, we present informally a new model for heterogeneous embedded systems, called HEMOC, which combines three common models of computation, synchronous reactive, hierarchical finite state machines and synchronous data flow. Then, the languages Esterel and SyncCharts are used for system specification following the new model in order to determine what they need to become suitable specification platform.

Design of 3-valued R-S & D type of flip-flops is described. A new clock is developed according to which circuit makes transition as well as retains present, past & former past information. The proposed flip-flops are constructed using clocked T-Gates that reduces the number of transistors required to implement single clocked gates. In the verification by simulation, the proposed flip-flops appears to have lesser power consumption and better speed of operation.

The system level hardware architecture of individual nodes in a distributed wireless sensor network has not received adequate attention. A novel hardware architecture based on the concept of task specific modular computing provides both the high flexibility and power efficiency required for effective distributed sensing solutions. This paper presents this newly developed architecture and provides an analysis of two possible methods for module interaction. Results from simulations based on this analysis are given. Finally, a brief description of the hardware and software design and prototype implementation of the modular architecture for sensor systems (MASS) is given to show the ease of use of the conceptual architecture.

This paper describes a high performance multiply-accumulator (MAC) unit in DSP-core. Since the most critical timing path of the DSP lies in the MAC, great endeavors have been paid to speed it up. The MAC unit can perform fixed-point operation with rounding optional, on operands with a throughput of 1 cycle. In this design, the modified sign extension algorithm is presented to eliminate the sign bits array of partial products to reduce computation time and area. Further increase in speed is achieved by using a new three 40 bit inputs (also known as operands) high-speed arithmetic logical unit (ALU) to shorten the delay of the critical path.

In this paper we present a multi-key index model that enables us to search a record with more than one attribute values in distributed database systems. Indices provide fast and efficient access of data and so become a major aspect in centralized database systems. Most of the centralized database systems use B₊ tree or other types of index structures such as bit vector, graph structure, grid file etc. But in distributed database systems no index model is found in the literature. Therefore efficient access is a major problem in distributed databases. Our proposed index model avoids the query-flooding problem of existing system and thus optimizes network bandwidth.

This paper describes a high-speed reconfigurable neural networks for monitoring operational status of automated machinery. Continuous operation of precision machines may change their system performance due to wear, deterioration, or failure. A Learning Vector Quantization (LVQ) based technique is developed that is capable of monitoring system status accurately, and updating its knowledge base with new heuristic data. This method is adapted for practical application to solve problems of condition monitoring and fault diagnosis where a number of fault signatures are initially available. In these situations, the aim is health monitoring, including identification of deterioration of the healthy condition and identification of causes of the failures. A hard real-time system is designed and implemented. An early-warning system monitors sensitive parameters of pressure and current sensors. Their variations beyond a defined healthy threshold trigger a non-destructive testing, which produces transient signals. Correlating the transient pattern of a fault with a database of known failures determines the severity and degree of deterioration of the system. Vigorous tests on real machines indicated an accuracy of 92.3% for the LVQ based monitoring system.

The purpose of this paper is to present a new hybrid Elastic Net (EN) algorithm, by integrating the ideas of the Self Organization Map (SOM) and the strategy of the gradient ascent into the EN algorithm. The new hybrid algorithm has two phases: an EN phase based on SOM and a gradient ascent phase. We acquired the EN phase based on SOM by analyzing the weight between a city and its converging and non-converging nodes at the limit when the EN algorithm produces a tour. Once the EN phase based on SOM stuck in local minima, the gradient ascent algorithm attempts to fill up the valley by modifying parameters in a gradient ascent direction of the energy function. These two phases are repeated until the EN gets out of local minima and produces the short or better tour through cities. We test the algorithm on a set of TSP. For all instances, the algorithm is showed to be capable of escaping from the EN local minima and producing more meaningful tour than the EN.

In this paper we present a global optimization method for multiple objective functions using the Pareto Simulated Annealing (SA). This novel optimization method is very useful and promising for design and application in the field of Micro-Electro-Mechanical Systems (MEMS). Previously published global optimization method has been reported by us for only single objective function. The proposed method automatically assigns different objective weights to each objective functions so that it can generate multiple solutions simultaneously. It also offers the trade-off between the objective functions so that we will be able to select the most suitable solution for MEMS design and applications. Based on the global Pareto ranking of the solutions, the optimization method can provide the best solution (the first Pareto ranking) as well.

Existing low power schedules mainly try to decrease overall system energy usage by shutting down unused devices after process scheduling. This often leads to suboptimal energy usage due to the lack of process slack time to shut down unused devices in a fixed system schedule such as that generated by a rate-monotonic or an earliest deadline first scheduler in a real-time embedded system. In this work, we try to integrate process scheduling with low power scheduling such that a low-power real-time feasible schedule is obtained. The proposed method called Low-Power Quasi-Dynamic Scheduling (LQS) was implemented and applied to some examples, including a sensor network node and Bluetooth devices, to prove its benefits.

Dynamic optimization problems with linear hybrid (discrete/continuous) systems embedded whose transition times vary are inherently nonconvex. For a wide variety of applications, a certificate of global optimality is essential, but this cannot be obtained using conventional numerical methods. We present a deterministic framework for the solution of such problems in the continuous time domain. First, the control parametrization enhancing transform is used to transform the embedded dynamic system from a linear hybrid system with scaled discontinuities and varying transition times into a nonlinear hybrid system with stationary discontinuities and fixed transition times. Next, a recently developed convexity theory is applied to construct a convex relaxation of the original nonconvex problem. This allows the problem to be solved in a branch-and-bound framework that can guarantee the global solution within epsilon optimality in a finite number of iterations.