An information-theoretical framework for modeling component-based systems

Software systems tend to be large scale and complex with the inevitable increase in their functionalities. The increasing costs related to system development and maintenance in correlation to the software size requires new assessment tools for the newly evolving development methodologies. Taking advantage of existing tools and methodologies in a mature field is beneficial to relatively young, related disciplines. Therefore, this paper brings modeling techniques from a well-developed and mature discipline, information theory, into component-based software (CBS) engineering. Information-theoretic representation and analysis techniques in general, noiseless information channel concepts in particular, are good candidates to be adopted to model the dynamic behavior of software components and quantify the interaction between them. This modeling approach is realized by first modeling the component integration units of CBS with cubic control flowgraphs. The arcs in these models can be labeled as functions of parameters of their "hidden" components in the originating nodes or arcs, or both. Each of these labeled graphs defines a Shannon language. Then, a set of metrics, labeled as pervasive Shannon metrics is defined. Four case studies are demonstrated to show the applicability of the proposed metrics for assessment of CBS.     

Design and simulation of component-based manufacturing machine systems

This paper presents the modular machine design environment (MMDE), a software environment that enables the ‘virtual design/engineering' of component-based manufacturing machine systems. It consists of a suite of highly integrated tools supporting the visualisation, design, programming, verification and evaluation of machine systems built from mechanical, electronic and software components/modules in a virtual environment. Using three-dimensional (3-D) graphical simulation with a number of add-on tools, MMDE supports visualisation, design, simulation and verification of both the physical model and control logic for design and/or re-configuring machine systems to satisfy new or changed application/customer requirements before any real implementation is made. System design, implementation techniques, and evaluation of MMDE in a real industrial test case are covered in detail.     

Performance evaluation of data communication systems

This paper is a tutorial and a survey of analytical methods in the evaluation of data communication networks. The major mathematical methods are Markov chains applied to discrete time systems and queueing theory. Emphasis is placed on the applications of the mathematical tools. The discussion follows the framework of the layered architecture. In the section on data link control, rigorous as well as "engineering" approaches are highlighted. In this area, models of great accuracy have been developed. In the path-control or routing layer, the major model is provided by Kleinrock's delay analysis of packet networks. Finite buffer pools still pose many problems. The method of the homogeneous network is introduced, a method which reduces complexity originating from the network topology in favor of more realistic protocol features. This thought is expanded into the layer of end-to-end protocols where the tandem-queue model is introduced and its application to the flow-control problem discussed.     

Performance evaluation of optical fiber transmission systems

A method is presented for evaluating of error probability for optical-fiber communication systems in the present of intersymbol interference and additive noise. It is based on deriving a best approximation, in a minimax sense, for the cumulative distribution function of the additive noise. The method takes into account the avalanche photodetector's non-Gaussian shot noise statistics. The additive noise is also not constrained to be Gaussian. Examples are presented for comparison to previously published techniques     

Performance evaluation of generalized multi-state k-out-of-n systems

The generalized multi-state k-out-of-n:G system model defined by Huang provides more flexibilities for modeling of multi-state systems. However, the performance evaluation algorithm they proposed for such systems is not efficient, and it is applicable only when the k/sub i/ values follow a monotonic pattern. In this paper, we defined the concept of generalized multi-state k-out-of-n:F systems. There is an equivalent generalized multi-state k-out-of-n:G system with respect to each generalized multi-state k-out-of-n:F system, and vice versa. The form of minimal cut vector for generalized multi-state k-out-of-n:F systems is presented. An efficient recursive algorithm based on minimal cut vectors is developed to evaluate the state distributions of a generalized multi-state k-out-of-n:F system. Thus, a generalized multi-state k-out-of-n:G system can first be transformed to the equivalent generalized multi-state k-out-of-n:F system, and then be evaluated using the proposed recursive algorithm. Numerical examples are given to illustrate the effectiveness and efficiencies of the proposed recursive algorithms.     

Performance evaluation of ASK phase-diversity lightwave systems

Phase diversity coherent systems are gaining increasing interest with the increase of the bit rate in optical transmissions. In this work, an accurate approach for the evaluation of the error probability in ASK phase-diversity lightwave systems is presented. The approach is based on a Gaussian quadrature rule integration, which takes into account the exact characterization of the filtered phase noise through its moments. The effects of the laser linewidth on the error probability for hybrid circuits with different number of ports are derived and discussed. Also, the effects of the frequency offset are considered     

Performance evaluation of optically pre-amplified PPM systems

An original analysis is presented for an optical fiber n-ary pulse position modulation (PPM) system employing optical preamplification. The theoretical results, from calculations performed at a bit-rate of 622 Mbit/s and a wavelength of 1.53 μm, demonstrate that the PPM system offers a 7.5 dB sensitivity benefit in comparison with an equivalent PCM system. Furthermore the results illustrate that optically preamplified PPM offers sensitivities significantly better than the fundamental limit of an optically preamplified PCM system and in fact approaches that of coherent detection     

Performance evaluation of multicast MISO–OFDM systems

In this paper, we analyze the performance of multicast orthogonal frequency division multiplexing (OFDM) systems with single and multiple transmit antennas. We show that the resource allocation that includes the subcarrier allocation, bit loading, and the precoding vector selection in the multiple-input single-output (MISO) case is a difficult optimization problem. Consequently, we propose suboptimal algorithms based on the maximization of the sum data rate and the maximization of the minimum user data rate criteria. For practical application, we consider a complete transmission chain by combining powerful erasure codes with the proposed algorithms. Using this scheme, we guarantee that each user receives the same amount of information to decode the same data. Simulation results show that, for both single-input single-output (SISO)–OFDM and MISO–OFDM cases, the proposed multicast OFDM systems achieve gains over the worst user case algorithm.     

Performance evaluation of monitoring IoT systems using LoRaWan

The proliferation of smart devices, or even better, IoT devices, has led to the widespread development of applications that take advantage of these devices. Of particular interest is the precise localization of such a device. However, these use cases become extremely difficult when connectivity to end-devices is required even in areas where the signal is too low or different technologies co-exist for the transmission of the data. In this research work, we study LoRaWan and Wi-Fi as two possible candidates for data transmission. We are particularly focused on the study of the above technologies in terms of performance as well as application development that can be used as rescue monitoring systems. For this reason, we start by describing LoRa as an ideal low power and long-distance communication protocol on the IoT devices compared to the Wi-Fi network. We perform various simulations in terms of time on air transmission, bit error rate by changing important metrics to study the behavior of the whole mechanism. Based on our simulations, the main findings highlight that the contribution of a spreading factor and bandwidth optimizations can be applied to real hardware for real search and rescue (SAR) cases giving improved results in case of coverage and battery extension applications. As a continuation of our research, we developed a monitor application that collects and visualizes data from end-nodes (wearables). These data are processed gateway and network server to The Things Network (TTN) for further analysis. The proposed solution can be used in different rescue monitor scenarios such as identifying and find individuals of vulnerable groups or those belonging to group of people with a high probability of being lost. The purpose of the above solution is to overcome monitor problems on SAR cases, compare with WiFi and suggest a module supporting both technologies in order to be used in real experiments.

     

Performance evaluation of optical code division multiple access systems

In this paper, a new mechanism of faster routing known as message priority and fast routing (MPFR) mechanism in optical code division multiple access (OCDMA) is proposed for optimization of routing performance and to provide effective data transfer. In this proposed work, we have reduced the size of the header bits which are used in MPFR mechanism. In proposed algorithm, with accordance to packet header, the message size is being increased and priority bit is being added which leads to faster data transfer rate and effective data transfer in OCDMA. The transmitter sent the 2D codes to the MPFR which is then added priority bit. If the cover bit in any codes is enabling then the code is considered to be a priority packet and its superior bit then the code is considered to be routing. A modern novel approach which reduces the overhead for fast data transfer is proposed on name of MPFR. Thus the routing can be faster and the codes to be sent are being priorities and send. Thus the OCDMA can now become much faster to be used in critical areas. MPFR protocol, which prioritizes the code with high priority and also it reduces the header processing time of the codes with increase in message size. The prioritization of the code helped to process the particular code first and then rest of the codes and with increase in message size, help to reduce the transmission and processing time of the packet header.     

Performance evaluation of polling systems for wireless localcommunication networks

This paper evaluates the performance of different polling systems used in wireless local networks where the transmission channel exhibits a nonstationary behavior. Many spatially dispersed data user terminals have been assumed to share a common short-range radio uplink channel to access a hub station. We have specifically considered cyclic polling systems with M queues (terminals), having the same general packet arrival process and general switchover period. The gated and exhaustive disciplines have been considered in ordering the transmission of the packets buffered at each terminal. By appropriately modeling the uplink channel, we propose analytical approaches to derive the average packet waiting time and the average cycle length for gated polling systems, combined with stop-and-wait (SW) and go-back-N (GBN) automatic repeat request (ARQ) techniques to control errors. A gated cyclic polling scheme combined with the selective-repeated (SR) stutter ARQ technique as well as an exhaustive cyclic polling scheme combined with SW, GBN, or SR stutter ARQ techniques, respectively, have also been considered In order to give an in-depth knowledge of the behavior of suitable polling alternatives for applications in wireless local communication networks     

Performance evaluation of mobile wireless communication systems with link adaptation

The performance of key quality-of-service metrics for mobile cellular systems with link adaptation is evaluated by means of a teletraffic analysis. To our knowledge, no similar analysis considering link adaptation exists in the literature. In particular, novel mathematical expressions for inter-cell handoff call arrival rate, intracell handoff failure, and forced termination probabilities are derived.     

Performance evaluation of uplink power control algorithm over TDMA systems

Future PCS (personal communication system) cellular networks will mainly be driven by high link quality, high bandwidth utilization, low power consumption and efficient network management. Power control is one of the several major techniques which could help to achieve these goals. By exploiting power control techniques, co-channel interference could be reduced and as many links as possible could be obtained with satisfactory link quality. SIR-based (signal-to-interference ratio-based) power control was proposed as a technique for managing co-channel interference in cellular radio systems. Furthermore, new distributed autonomous feedback power control methods were introduced to achieve excellent performance without the difficult centralized control used in SIR-based methods. Unfortunately, the implementation of those power control algorithms is still challenging owing to the precision of SIR. The main aim of this paper is to investigate an uplink power control algorithm which depends indirectly on the signal-to-noise ratio in the TDMA (time division multiple access) cellular system. Simulation of the prototype hardware implementation of the receiver baseband signal processing based on the PACS (personal access communications system) specification is used as the main approach to explore the performance evaluation of this power control technique. According to simulation results, suitable values of those parameters used in this power control algorithm are derived, and the minimum frequency reuse factor under different propagation environments is also obtained for PACS under power control. © 1998 John Wiley & Sons, Ltd.     

Performance evaluation for multichannel access schemes in CDMA cellular systems

The CDMA system promisingly provides more capacity than AMPS. However, providing multichannels for a CDMA system is a requisite to satisfy the demanded capacity. In this paper, five schemes of multichannel assignment are proposed. Based on computer simulation, performance measures such as blocking probabilities, the overall capacity, the capacity of each channel and the number of retrials are obtained. Simulation results indicate that the SIR-based selection scheme is preferable to the other schemes. © 1998 John Wiley & Sons, Ltd.     

mPower — a component-based development framework for multi-agent systems to support business processes

One of the obstacles preventing the widespread adoption of multi-agent systems in industry is the difficulty of implementing heterogeneous interactions among participating agents via asynchronous messages. This difficulty arises from the need to understand how to combine elements of various content languages, ontologies, and interaction protocols in order to construct meaningful and appropriate messages. In this paper mPower, a component-based layered framework for easing the development of multi-agent systems, is described, and the facility for customising the components for reuse in similar domains is explained. The framework builds on the JADE-LEAP platform, which provides a homogeneous layer over diverse operating systems and hardware devices, and allows ubiquitous deployment of applications built on multi-agent systems both in wired and wireless environments. The use of the framework to develop mPower^mobile, a multi-agent system to support mobile workforces, is also reported.     

Performance evaluation of optical CDMA systems using non-coherentdetection and bipolar codes

The efficiency of an asynchronous optical CDMA (code-division multiple access) system is addressed. Two types of data modulations are considered: ASK and large-deviation CPFSK. Each user's narrow-band information is spread by the use of an electrooptic phase modulator. The sequences considered are bipolar Kasami and Gold codes. The receiver consists of an optical filter of bandwidth ≈1/T, to filter the interfering signals, followed by simple, noncoherent detection. We thereby avoid all the difficulties usually met with coherent detection. Moreover, this type of demodulation is particularly suitable for a hybrid WDMA/CDMA (wavelength-division multiple access/code division multiple access) system where the spread-spectrum technique allows multiple users to share the same wavelength, thereby increasing the capacity of the network. Results are given in terms of the number of interfering signals that can be tolerated for different code periods N, and for an acceptable P_e. Comparison is made relative to the Gaussian approximation on the distribution of the interfering signals     

Performance evaluation of impulse radio UWB systems with pulse-based polarity randomization

In this paper, the performance of a binary phase shift keyed random time-hopping impulse radio system with pulse-based polarity randomization is analyzed. The effects of interframe interference and multiple-access interference on the performance of a generic Rake receiver are investigated for asynchronous systems in frequency-selective environments. A key step is to model the asynchronous system as a chip-synchronous system with uniformly distributed timing jitter for the transmitted pulses of interfering users. This model allows the analytical technique developed for the synchronous case to be extended to the asynchronous case and allows the derivation of closed-form equations for the bit error probability in various Rake receiver architectures. It is shown that a Gaussian approximation can be used for both multiple-access and interframe interference as long as the number of frames per symbols is large (typically, at least 5), whereas there is no minimum requirement for the number of users for the equations to hold. It is observed that under many circumstances, the chip-synchronous case shows a worse bit error probability performance than the asynchronous case; the amount of the difference depends on the autocorrelation function of the ultra-wideband pulse and the signal-to-interference-plus-noise-ratio of the system. Simulations studies support the approximate analysis.     

Performance evaluation of nonsynchronized initial random access for mobile broadband systems

In this paper, a comparative analysis of the performance of the nonsynchronized initial random access channel in Mobile WiMAX and E-UTRA systems under different conditions (fast fading, multiuser interference) is carried out. The analysis is focused on the correlation properties of the code sequences used in each case. We evaluate their ability to provide low values for false alarm and erroneous detection probabilities (detecting a sequence that has not been transmitted) at the same time as guaranteeing low nondetection probabilities of the effectively transmitted sequences. Results show the promising performance of the E-UTRA scheme, even in high mobility scenarios, where the Doppler effect requires additional considerations to guarantee the correct system operation.