Significant Increase In System Performance Research Articles

Robust interference cancellation for differential quadrature phase-shift keying modulation with band limiting and adaptive filter

Differential quadrature phase-shift keying (DQPSK) modulation techniques and their variants are widely applied in digital communication, such as for high-speed optical fiber, bluetooth, or satellite communication. In its implementation, DQPSK cannot be separated from the potential harmful interference. In this research, a system model has been made for observation and analysis of the interference cancellation process. Discrete finite-duration impulse response (FIR) filters for band limiting and adaptive filter are the key components of the supporting block for this system model. Robust Simulink results have shown a significant increase in system performance in the existence of these key components. The indication has been shown by the best bit error rate (BER) of 3.3e-05. Constellation and eye pattern diagrams have supported the BER.

Improving radar performance with constant envelope multi-level chirp

M-level Continuous Phase Chirp Modulation is considered for data transmission. In this article, we would like to propose a new approach to transmitting information with the help of multi-level wave guide signaling. The main problem with the classic chirp modulation system is that the final phase of the signal is not equal in each period to the initial phase of the next step, and this discontinuity is present in each data transmission period. The main objective of this paper is to improve the efficiency of chirp modulation, which is recommended for continuous phase multi-level scalar modulation, which results has a significant increase in system performance. In this new approach, for sending the M symbols, we use the M level to send the message. With the help of this idea, we simulate the telecommunication system and examine the probability of its bit error in the presence of additive white Gaussian noise and Rician fading.

Using simulation as an adaptive source of knowledge for the control of material handling systems

Recent advances in computing have allowed simulation to be used as a source of data in the real-time control of logistics systems such as Material Handling Systems (MHS). For a real-world MHS, in development by Lödige Industries GmbH, Germany, we demonstrate the benefit of generating data offline using a parametrized simulation model that real-time operational control is based on. The data consist of mappings of control situations to optimal actions respectively. Our approach allows for self-adaptation of the simulation by observing current system parameters that are fed into the model. The control automatically triggers regeneration when necessary, detects changes in the system and also proactively anticipates them, resulting in consistently high performance. We furthermore use a simulation-based look-ahead method to consider uncertainties when evaluating alternative actions. Evaluation results show a significant increase in system performance compared to fixed application of a control action and demonstrate the benefits of the self-adaptive properties.

Structuring waveguide-grating-based wavelength-division multiplexing/optical code division multiple access network codecs over topology of concentric circles

The cyclic period and free spectral range of arrayed-waveguide gratings (AWG) in a wavelength-division multiplexing/optical code division multiple access optical code division multiple access network are exploited. The total optical network unit (ONU) of network capacity is partitioned into groups of different wavelength in accordance with the geographical location of subscribers based on the radial distance of the ONU to the optical line terminal. Combining concentric circles round by round for ONU groups enables a fixed round-trip time in the data transmission and a significant increase in system performance. Using AWG router, the proposed topology of concentric circles retains signature orthogonality and minimizes wavelength collisions on the photo-detector. Furthermore, the adoption of extended M-sequence codes corresponding to the AWG codec provides a simpler, more efficient coding procedure and accommodates more users in a single group.

Optimum performance of a heat engine‐driven combined vapour compression–absorption–ejector heat pump

Optimum performance of an endoreversible heat engine-driven heat pump cycle, based on a combination of an absorption cycle with a vapour and ejector compression cycles is investigated. This combination increases the performance of the conventional ejector and absorption cycles and provides high performance for heating. The analysis show that the combined heat pump cycle has a significant increase in system performance over the heat engine-driven vapour compression or absorption heat pump cycle and heat engine-driven combined vapour compression and absorption heat pump cycle. Copyright © 2000 John Wiley & Sons, Ltd.

Performance analysis of a heat engine driven combined vapor compression–absorption–ejector refrigerator

An endoreversible heat engine driven refrigeration cycle based on the combination of an absorption cycle with vapor and ejector compression cycles is described. This integration maximizes the performance of the conventional ejector and absorption cycles and provides high performance for refrigeration. The analysis shows that the combined cycle has a significant increase in system performance over the heat engine driven vapor compression refrigerators and heat engine driven combined vapor compression and absorption refrigerators.

Optimum performance of a heat engine-driven combined vapour compression-absorption-ejector heat pump

Optimum performance of an endoreversible heat engine-driven heat pump cycle, based on a combination of an absorption cycle with a vapour and ejector compression cycles is investigated. This combination increases the performance of the conventional ejector and absorption cycles and provides high performance for heating. The analysis show that the combined heat pump cycle has a significant increase in system performance over the heat engine-driven vapour compression or absorption heat pump cycle and heat engine-driven combined vapour compression and absorption heat pump cycle. Copyright © 2000 John Wiley & Sons, Ltd.

Optimal performance of an irreversible, heat engine-driven, combined vapor compression and absorption refrigerator

By employing finite-time thermodynamic approach, the optimum performance of an irreversible heat engine-driven combined vapor compression and absorption refrigerator system is investigated. To get closer to real machines, the effects of thermal resistances and internal irreversibilities on the performance of the combined cycle is considered. The analysis show that the combined cycle has a significant increase in system performance over the heat engine-driven vapor-compression refrigerators.

Evaluation of a combined ejector-vapour-compression refrigeration system

A new refrigeration cycle based on the combination of an ejector cycle with a vapour compression cycle is described. This integration maximizes the performance of the conventional ejector cycles and provides high COP for refrigeration. The analyses show that the new cycle has a significant increase in system performance over the conventional systems, its COP values are competitive to the absorption machines. If the system is powered by waste heat and the cost of its supply can be neglected, the COP values will be much higher. The system performance can be further improved if dual refrigerants are used and the dual refrigerants giving high performance are identified. © 1998 John Wiley & Sons, Ltd.