Total System Capacity Research Articles

An integrated reservoir-power system model for evaluating the impacts of wind integration on hydropower resources

Despite the potential for hydroelectric dams to help address challenges related to the variability and unpredictability of wind energy, at present there are few systems-based wind-hydro studies available in the scientific literature. This work represents an attempt to begin filling this gap through the development of a systems-based modeling framework for analysis of wind power integration and its impacts on hydropower resources. The model, which relies entirely on publicly available information, was developed to assess the effects of wind energy on hydroelectric dams in a power system typical of the Southeastern US (i.e., one in which hydropower makes up <10% of total system capacity). However, the model can easily reflect different power mixes; it can also be used to simulate reservoir releases at self-scheduled (profit maximizing) dams or ones operated in coordination with other generators to minimize total system costs. The modeling framework offers flexibility in setting: the level and geographical distribution of installed wind power capacity; reservoir management rules, and static or dynamic fuel prices for power plants. In addition, the model also includes an hourly ‘natural’ flow component designed expressly for the purpose of assessing changes in hourly river flow patterns that may occur as a consequence of wind power integration. Validation of the model shows it can accurately reproduce market price dynamics and dam storage and release patterns under current conditions. We also demonstrate the model's capability in assessing the impact of increased wind market penetration on the volumes of reserves and electricity sold by a hydroelectric dam.

Performance approximations and bounds for non‐real‐time traffic in an integrated service system

The authors consider an integrated service system, where real-time (RT) calls of multiple rate requirements and non-real-time (NRT) calls share the total system capacity. Typically, RT calls are given strict priority over NRT calls; therefore NRT performance is dependent on the RT process. When RT call arrivals do not follow a Poisson process, the effect of the RT traffic burstiness on the NRT performance has not been investigated. In this study, the authors investigate this effect and provide computationally efficient approximations and bounds for the NRT performance evaluation in the integrated service system with multi-rate non-Poisson RT traffic. With known first and second moments of the RT call arrival processes, the authors propose to consider the multi-rate non-Poisson RT traffic streams as an equivalent single-rate Poisson traffic stream. Then, the authors evaluate the NRT performance by converting the original system to a system offered with the equivalent RT traffic and the NRT traffic. The authors’ approximations and bounds are validated by extensive numerical examples.

Abstract T P259: What Should Really be Happening to Our Stroke Patients Post-Acute Care?: A System Best Practice Model for Inpatient Rehab

Background: A regional Stroke Report Card identified poor performance on system efficiency, effectiveness, and integration of stroke best practice. This engaged regional funders and 17 organizations (11 acute, 6 rehab) to collaborate in stroke system planning. The focus included stroke unit care and access to timely and appropriate rehabilitation, including increased access for severe stroke. Changes in acute care, including pre-hospital, have facilitated access to stroke unit care in the city. A model of patient flow from acute care was needed to understand other system capacity needs. Purpose: To use best practice and benchmarks to delineate post-acute patient flow and facilitate alignment of resources for inpatient rehabilitation. Methods: Administrative data from national reporting and local rehab referral system databases were used to review current system usage from acute care. A model of proportional distribution of cases from acute, specifically to inpatient rehab, was established using provincial benchmarks, evidence informed targets, and organization market share of total inpatient rehab system capacity. Iterative discussions were required to confirm the organizations’ commitment to stroke best practice. New volume and case mix changes were applied to determine capacity and resource planning needs across organizations. Results: The best practice model, approved by all stakeholders, proposes 40% of stroke patients discharged alive from acute care should access inpatient, 13% outpatient rehabilitation and 6% to Complex Continuing Care and Long Term Care. Current practice is 26%, &lt;5% and 13% respectively. A projected volume increase of 278 patients is distributed across 5/6 rehab providers. This results in a total proportional system shift from 20% (n=160) to 41.5% (n =446) of severe patients receiving access to high intensity rehab. A reduction in the overall proportion of moderate and mild stroke patients from 65% (519) to 49.5% (n=534) and 15% (n=119) to 9% (n=96) respectively. Conclusion: Significant investment/redistribution of resources within the system is required to support patient flow and provide care in the right place at the right time. System funder support is critical to create a quality of care (best practice) system.

Optimization of Power Allocation for a Multibeam Satellite Communication System with Interbeam Interference

In multibeam satellite communication systems it is important to improve the utilization efficiency of the power resources, due to the scarcity of satellite power resources. The interbeam interference between the beams must be considered in the power allocation; therefore, it is important to optimize the power allocated to each beam in order to improve the total system performance. Initially the power allocation problem is formulated as a nonlinear optimization, considering a compromise between the maximization of total system capacity and the fairness of the power allocation amongst the beams. A dynamic power allocation algorithm based on duality theory is then proposed to obtain a locally optimal solution for the optimization problem. Compared with traditional power allocation algorithms, this proposed dynamic power allocation algorithm improves the fairness of the power allocation amongst the beams, and, in addition, the proposed algorithm also increases the total system capacity in certain scenarios.

Optimization of Joint Power and Bandwidth Allocation in Multi-Spot-Beam Satellite Communication Systems

Multi-spot-beam technique has been widely applied in modern satellite communication systems. However, the satellite power and bandwidth resources in a multi-spot-beam satellite communication system are scarce and expensive; it is urgent to utilize the resources efficiently. To this end, dynamically allocating the power and bandwidth is an available way. This paper initially formulates the problem of resource joint allocation as a convex optimization problem, taking into account a compromise between the maximum total system capacity and the fairness among the spot beams. A joint bandwidth and power allocation iterative algorithm based on duality theory is then proposed to obtain the optimal solution of this optimization problem. Compared with the existing separate bandwidth or power optimal allocation algorithms, it is shown that the joint allocation algorithm improves both the total system capacity and the fairness among spot beams. Moreover, it is easy to be implemented in practice, as the computational complexity of the proposed algorithm is linear with the number of spot beams.

A study of BIPV net-zero energy building

The purpose of this paper is to analyze the power performance and power generation of a BIPV system built in HsinChu, Taiwan, during 2011-2012. The total PV energy generation is 5,960 kWh and the energy consumption is 7,257 kWh in 2011. After insulation works and setting the standards of electrical equipment operating time, the BIPV building achieves net zero energy goal in 2012. The total PV energy generation is 5,329 kWh and the energy consumption is 4,202 kWh. The self-powered ratio of renewable energy was 126.8% in the whole BIPV house. In this research, we investigated on the four different types of PV module for the net zero energy research project. The total system capacity is 8.04 kWp, and the system was installed at sloping roof, wall, window and shading. The BIPV Experiment-Demo House is a good example of using renewable energy and some energy saving measures to achieve net zero energy building.

In Vivo Antioxidant and Anti-Skin-Aging Activities of Ethyl Acetate Extraction from Idesia polycarpa Defatted Fruit Residue in Aging Mice Induced by D-Galactose.

Two different concentrations of D-galactose (D-gal) induced organism and skin aging in Kunming mice were used to examine comprehensively the antioxidant and antiaging activities of ethyl acetate extraction (EAE) from Idesia polycarpa defatted fruit residue for the first time. The oxygen radical absorbance capacity (ORAC) of EAE was 13.09 ± 0.11 μmol Trolox equivalents (TE)/mg, which showed EAE had great in vitro free radical scavenging and antioxidant activity. Biochemical indexes and morphological analysis of all tested tissues showed that EAE could effectively improve the total antioxidant capacity (T-AOC) of the antioxidant defense system of the aging mice, enhance the activities of superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px) of tissues and serum, increase glutathione (GSH) content and decrease the malondialdehyde (MDA) content, and maintain the skin collagen, elastin, and moisture content. Meanwhile, EAE could effectively attenuate the morphological damage in brain, liver, kidney, and skin induced by D-gal and its effect was not less than that of the well-known L-ascorbic acid (VC) and α-tocopherol (VE). Overall, EAE is a potent natural antiaging agent with great antioxidant activity, which can be developed as a new medicine and cosmetic for the treatment of age-related conditions.

MODELING FIELD GEOMETRY OF MICRO-IRRIGATION SYSTEMS

The purpose of planning an irrigation network is to achieve suitable water distribution and to satisfy the hydraulics and economic rules. A model was developed to design, plan and manage an irrigation system subject to a number of constraints according to field geometry, soil properties, plant characteristics and irrigation system parameters. As a result, management criteria may be achieved by selecting a layout pattern and the appropriate number of shifts. The Microsoft Excel Solver tool was used to solve the partitioning part. The model divides the field into subunits. The decision variables are: 1) pipe lengths and diameters (lateral, riser, manifold, auxiliary, submain and main). 2) The total number of subunits, number of sets (subunit parallel to the main line). 3) Number of submain lines perpendicular to the main line. 4) Possible numbers of shifts and shift time. 5) List of system equipment. 6) Pump total dynamic head, system capacity and pump power. 7) Cost analysis of the system and total capital cost. The model was successfully solved the problem of partitioning the field and specifies the dimension of different parts of the micro irrigation system network. The planning of the irrigation field layout accomplished among five patterns (A through E). The validity of the model was extended to select the economic pipe sizes and estimate the system total costs in case of one shift operation policy or at a higher number of shifts to reduce the cost. Throughout a case study to plan design and management of 20 fed. (300 m length and 280 m width) to irrigate trees 5mx5m spacing, results indicated that pattern E was the most economic option either in operating the system in one shift (the cost is 7348 LE.fed) or to reduce further cost to be 3861 L.E./fed.) in case of operate the system in four shifts. Investigating the effect of system area ranged between 5 to 50 feddan on system total cost indicated that the cost increased linearly proportional to the increasing of the system area. The effect of number of shifts on total cost was also studied. The results showed that the relationship is power function where the total cost is inversely proportional to increasing the number of shifts.

Optimization of Power Allocation for Multiusers in Multi-Spot-Beam Satellite Communication Systems

In recent years, multi-spot-beam satellite communication systems have played a key role in global seamless communication. However, satellite power resources are scarce and expensive, due to the limitations of satellite platform. Therefore, this paper proposes optimizing the power allocation of each user in order to improve the power utilization efficiency. Initially the capacity allocated to each user is calculated according to the satellite link budget equations, which can be achieved in the practical satellite communication systems. The problem of power allocation is then formulated as a convex optimization, taking account of a trade-off between the maximization of the total system capacity and the fairness of power allocation amongst the users. Finally, an iterative algorithm based on the duality theory is proposed to obtain the optimal solution to the optimization. Compared with the traditional uniform resource allocation or proportional resource allocation algorithms, the proposed optimal power allocation algorithm improves the fairness of power allocation amongst the users. Moreover, the computational complexity of the proposed algorithm is linear with both the numbers of the spot beams and users. As a result, the proposed power allocation algorithm is easy to be implemented in practice.

A Review of Cross-layer Design in Dynamic Spectrum Access for Cognitive Radio Networks

Cognitive Radio (CR) is an intelligent radio that can dynamically access the radio spectrum. Secondary users in Cognitive Radio Network (CRN) can access the licensed spectrum without causing harmful interference to primary users. The performance of cognitive radio networking functionalities depends on the properties of the spectrum band in use. This necessitates a crosslayer design in the entire CR networking protocol stack. Current researches are investigating different techniques of using cognitive radio to reuse more locally unused spectrums to increase the total system capacity. This paper provides a comprehensive survey of cross-layer design in cognitive radio network. The cross-layer design approach jointly considers the functions of the layers to maximize the performance of CR networks.

An Adaptive PRB, Power and MCS Allocation Using AMC for MIMO-OFDMA Systems

Long Term Evolution (LTE) is a promising technology for a high communication quality thanks to its radio link flexibility using Adaptive Modulation and Coding (AMC), Multiple Input Multiple Output (MIMO) and Orthogonal Frequency Division Multiple Access (OFDMA) technologies. In this paper, we address the adaptive resource allocation problem in down-link transmission of MIMO-OFDMA systems. We aim at maximizing the total system capacity to meet the 4G-technologies promises. In order to reduce the computational complexity, the original optimization problem is divided into sub-optimal ones. Firstly, a recursive Physical Resource Block (PRB) allocation algorithm is developed where the Effective Signal-to-Interference-plus-Noise Ratio (ESINR) metric is investigated to properly characterize the channel condition. Secondly, a power allocation procedure is performed. As all resource blocks allocated to the same user must use the same Modulation and Coding Scheme (MCS) according to the LTE standard requirements, power optimization sub-problem is divided into three steps: power allocation among PRBs, power allocation among antennas and power allocation among users. Finally, a more effective MCS is obtained, which ensures a better system capacity. Simulation results prove the efficiency of the proposed method to maximize the total system capacity with a low complexity even in the case of loaded systems compared to Minimum-MCS (Min-MCS) and Maximum-SINR (Max-SINR) algorithms.

Reliability of demand-based phased-mission systems subject to fault level coverage

In many real-world applications, a mission may consist of several different tasks or phases that have to be accomplished in sequence. Such systems are referred to as phased-mission systems (PMS). In this paper we consider the demand-based PMS with parallel structure, where the system components function in parallel with different capacities in each phase of the mission and the mission is successful if and only if the total system capacity meets the predetermined mission demand in each phase. The reliability of the demand-based PMS (DB-PMS) with parallel structure subject to fault-level coverage (FLC) is first studied using a multi-valued decision diagram (MDD) based technique. The traditional MDD is modified to accommodate the FLC mechanism and new MDD construction and evaluation procedures are proposed for DB-PMS. To reduce the size of the MDD, an alternative construction procedure applying the branching truncation method and new reduction rules are further proposed. An upwards algorithm is put forward to evaluate the reliability of DB-PMS subject to FLC. The proposed approaches are illustrated through examples.

Mitochondria express enhanced quality as well as quantity in association with aerobic fitness across recreationally active individuals up to elite athletes

Changes in skeletal muscle respiratory capacity parallel that of aerobic fitness. It is unknown whether mitochondrial content, alone, can fully account for these differences in skeletal muscle respiratory capacity. The aim of the present study was to examine quantitative and qualitative mitochondrial characteristics across four different groups (n = 6 each), separated by cardiorespiratory fitness. High-resolution respirometry was performed on muscle samples to compare respiratory capacity and efficiency in active, well-trained, highly trained, and elite individuals. Maximal exercise capacity (ml O(2)·min(-1)·kg(-1)) differed across all groups, with mean ± SD values of 51 ± 4, 64 ± 5, 71 ± 2, and 77 ± 3, respectively. Mitochondrial content assessed by citrate synthase activity was higher in elite trained compared with active and well-trained (29 ± 7 vs. 16 ± 4 and 19 ± 4 nmol·min(-1)·mg wet wt(-1), respectively). When normalizing respiration to mitochondrial content, the respiratory capacities during maximal fatty acid oxidation (P = 0.003), maximal state 3 respiration (P = 0.021), and total electron transport system capacity (P = 0.008) improved with respect to maximal exercise capacity. The coupling efficiency of β-oxidation, however, expressed no difference across groups. These data demonstrate the quantitative and qualitative differences that exist in skeletal muscle mitochondrial respiratory capacity and efficiency across individuals that differ in aerobic capacity. Mitochondrial-specific respiration capacities during β-oxidation, maximal oxidative phosphorylation, and electron transport system capacity all correspondingly improve with aerobic capacity, independent of mitochondrial content in human skeletal muscle.

A Recursive Resource Allocation Algorithm for MIMO-OFDMA Systems in Multi-user Context

This paper presents a new resource allocation algorithm for downlink multi-user MIMO-OFDMA systems. The main objective is to maximize the total system capacity and to guarantee the fairness among users with a low complexity. The proposed algorithm is based on a recursive sub-carriers allocation procedure aiming to satisfy Quality of Service (QoS) requirements for each mobile user. Simulation results demonstrate that the proposed algorithm performs well in terms of system capacity and fairness when the number of users in the cell is important closing to the practical case.

A Dynamic Bandwidth Allocation Scheme for a Multi-spot-beam Satellite System

A multi-spot-beam satellite is an attractive technique for future satellite communications since it can support high data rates by projecting high power density to each spot beam and can reuse a frequency in different cells to increase the total system capacity. In this letter, we propose a resource management technique adjusting the bandwidth of each beam to minimize the difference between the traffic demand and allocated capacity. This represents a reasonable solution for dynamic bandwidth allocation, considering a trade-off between the maximum total capacity and fairness among the spot beams with different traffic demands.

Adaptive Resource Allocation in MIMO-OFDMA based on Subcarrier Allocation (SA) and (GA)

In recent years, the eyes of scholars has been on the road to an proficient allocation scheme of signalling dimension between users in both uplink and downlink channels, since bandwidth is usually limited and/or very expensive. This paper covenants with the rate adaptive MIMO-OFDMA (Multiple Input Multiple Output-Orthogonal Frequency Division Multiplexing) downlink resource allocation scheme. It has an objective of maximizing the total system capacity subject to constraints on total power, bit error rate and proportional fairness. The proposed algorithm determines the number of subcarriers for each user and then handing over the subcarrier to each user. Two optimization methods, one based on Subcarrier Allocation (SA) and the other, based on Genetic Algorithm (GA) are used for resource allocation. In the optimization technique based on SA, using SVD (Singular Value Decomposition), the MIMO fading channel of each subcarrier is transformed into an equivalent bank of parallel SISO (Single Input Single Output) subchannels, which leads to a better trade-off strategy among system capacity, computational complexity and proportional fairness. Paralleled to static allocation schemes, the new algorithm has significantly lower complexity and in simulation fruitages higher system capacity. Simulation results show that the subcarrier allocation based on GA can provide capacity improvement with the reduction in fairness.

Performance Improvement of Heterogeneous Wireless Networks using Modified Newton Method

The heterogeneous wireless networks where coexistence of different Radio access technology (RAT) are widely deployed for various services and support various traffic demand, channel allocation. Under heterogeneous wireless networks, a user can send data throug h a single or multi RATs simultaneous. Th e objective of this paper is to choose the optimal bandwidth for the servicesand power allocation to that bandwidth. The proposed distributed joint allocation algorithm using modified Newton metho d is adopted to maximize the total system capacity. We validate the performance of the proposed algorithm through numerical results.

Thermal behavior in a 180-deg turned channel with the perforation divider under rotational condition

This study provided a new configuration of the 180-deg turned channel with a perforation divider. The perforations cross the divider let the coolant at the first duct to bypass into the second duct early, preventing from the local high temperature at the downstream zone. Additionally, the perforation-induced disturbing flow should enhance the total heat transfer. This work experimentally investigated the heat transfer behaviors of such system under the rotational condition. The results indicated that the perforation would reduce the raise of the local heat transfer at the turned region. Besides, the rotation would obviously influence the local heat transfer on the leading and trailing surfaces. Furthermore, the effect of rotation on the total heat transfer was insignificant. Finally, the perforation system with the relative perforation diameter d/Dh=2/4 had the similar total heat-transfer capacity with that without perforation; the total heat-transfer capacity of the perforation system with d/Dh=1/4 was around 20% higher than the non-perforation one.

Energetic, economic and environmental benefits of utilizing the ice thermal storage systems for office building applications

In recent decades, around the world, a huge amount of daytime peak power has been shifted to the off-peak hours by using different types of thermal energy storage systems. However, the contribution of these systems in Malaysia is still minor in comparison with their potential. Therefore, the feasibility and potentiality of employing ice thermal storage (ITS) systems for office building cooling applications is studied to investigate their economical and environmental benefits. The air conditioning systems in Malaysia are considered as the major energy consumers in office buildings with around 57% share. The economical analysis of the cost benefits is carried out for a system including chiller and storage system. The installation costs are mainly dominated by the total system capacity; hence the study was conducted for a range of 100–2000tons of refrigeration (TR) (352–7034kW) for two storage strategy of full storage and load levelling storage strategy. The results indicate that considering the special off-peak tariff rate of $0.06/kWh for the total system capacities of 500 and 1500TR (1758kW and 5275kW), the annual cost saving varies from $230,000 to $700,000 and from $65,000 to $190,000 for full storage and load levelling storage strategy, respectively. The overall results show that the full storage strategy can reduce the annual costs of the air conditioning system by up to 35% while this reduction is limited to around 8% for a load levelling strategy. The comparison study reveals that for the full storage strategy the payback period varies between 3 and 6 years while the payback period for the load levelling strategy varies between 1 and 3 years. It was concluded that the ITS system can play a vital role in consuming the natural resources in a more efficient, economical and environmentally benign way by changing the electricity consumption pattern to overcome the disparity between energy generation and energy demand.

Joint Power and Bandwidth Allocation Algorithm with QoS Support in Heterogeneous Wireless Networks

Heterogeneous wireless networks give rise to a multi-radio access environment which becomes crucial for load balancing to avoid network congestion and providing high quality services to maximize radio resource utilization. To this end, a joint power and bandwidth allocation with QoS support algorithm is proposed using convex optimization method in this letter. The algorithm achieves the goal of the total system capacity maximization, while efficiently satisfying the minimum rate constraint of delay-constraint service traffic and proportional fairness of best-effort service traffic. The simulation results show that the proposed algorithm significantly outperforms the existing scheme in QoS guarantee.