Modelling and analysis of type 4 wind turbine generator system for utilization in frequency regulation studies

Green energy targets for coming decades advocates high penetration of wind energy in main energy matrix which also pose incendiary threat to stability and reliability of modern electric grid if their dynamic performance aspects are not assessed beforehand. Considering increasing interest in dynamic performance along with ancillary service assessment related to frequency regulation, development of suitable generic modeling has gained high priority. This paper presents modeling of type 4 full converter wind turbine generator system suitable for frequency regulation focusing on active power control. Complete model is a modification of WECC generic model with additional aerodynamic and pitch control model. Descriptions of individual sub models are presented and performance results are compared manufacturer specific GE type 4 WTG generic model by means of simulations in the MATLAB ® Power System Block set.

Motivation and barriers for leisure-time physical activity in socioeconomically disadvantaged women

INTRODUCTION: The aim of this study was to examine cross-sectional and longitudinal associations between motivation and barriers for physical activity, and physical activity behavior in women living in socioeconomic disadvantage. This study also examined whether weight control intentions moderate those associations.

METHODS: Data from 1664 women aged 18-46 years was collected at baseline and three-year follow-up as part of the Resilience for Eating and Activity Despite Inequality study. In mail-based surveys, women reported sociodemographic and neighborhood environmental characteristics, intrinsic motivation, goals and perceived family barriers to be active, weight control intentions and leisure-time physical activity (assessed through the IPAQ-L). Linear regression models assessed the association of intrinsic motivation, goals and barriers with physical activity at baseline and follow-up, adjusting for environmental characteristics and also physical activity at baseline (for longitudinal analyses), and the moderating effects of weight control intentions were examined.

RESULTS: Intrinsic motivation and, to a lesser extent, appearance and relaxation goals for being physically active were consistently associated with leisure-time physical activity at baseline and follow-up. Perceived family barriers, health, fitness, weight and stress relief goals were associated with leisure-time physical activity only at baseline. Moderated regression analyses revealed that weight control intentions significantly moderated the association between weight goals and leisure-time physical activity at baseline (β = 0.538, 99% CI = 0.057, 0.990) and between intrinsic motivation and leisure-time physical activity at follow-up (β = 0.666, 99% CI = 0.188, 1.145). For women actively trying to control their weight, intrinsic motivation was significantly associated with leisure-time physical activity at follow-up (β = 0.184, 99% CI = 0.097, 0.313).

CONCLUSIONS: Results suggest that, especially in women trying to control their weight, intrinsic motivation plays an important role in sustaining physical activity participation over time. Also, weight goals for being physically active seem to play a role regarding short-term physical activity participation in this particular population. Addressing these motivational features may be important when promoting physical activity participation in women living in socioeconomically disadvantaged neighborhoods.

Emergency nurse practitioner care and emergency department patient flow: case-control study

Objective: The present study aimed to compare ED waiting times (for medical assessment and treatment), treatment times and length of stay (LOS) for patients managed by an emergency nurse practitioner candidate (ENPC) with patients managed via traditional ED care. Methods: A case–control design was used. Patients were selected using the three most common ED discharge diagnoses for ENPC managed patients: hand/wrist wounds, hand/wrist fractures and removal of plaster of Paris. The ENPC group (n = 102) consisted of patients managed by the ENPC who had ED discharge diagnoses as mentioned above. The control group (n = 623) consisted of patients with the same ED discharge diagnoses who were managed via traditional ED care. Results: There were no significant differences in median waiting times, treatment times and ED LOS between ENPC managed patients and patients managed via traditional ED processes. There appeared to be some variability between diagnostic subgroups in terms of treatment times and ED LOS. Conclusion: Patient flow outcomes for ENPC managed patients are comparable with those of patients managed via usual ED processes.

An active stereo vision-based learning approach for robotic tracking, fixating and grasping control

In this paper, an active stereo vision-based learning approach is proposed for a robot to track, fixate and grasp an object in unknown environments. First, the functional mapping relationships between the joint angles of the active stereo vision system and the spatial representations of the object are derived and expressed in a three-dimensional workspace frame. Next, the self-adaptive resonance theory-based neural networks and the feedforward neural networks are used to learn the mapping relationships in a self-organized way. Then, the approach is verified by simulation using the models of an active stereo vision system which is installed in the end-effector of a robot. Finally, the simulation results confirm the effectiveness of the present approach.

Using information flow model to specify the Kanban-controlled shopfloor control system

The implementation of Kanban-based production control systems may be difficult in make-to-order environments such as job shops. The flexible manufacturing approach constitutes a promising solution to adapt the Kanban method to such environments. This paper presents an information flow modelling approach for specifying the operational planning and control functions of the Kanban-controlled shopfloor control system (KSCS) in a flexible manufacturing environment. By decomposing the KSCS control functionalities, we have created the system information flow model through the data flow diagrams of Structured Systems Analysis Methodology. The data flow diagrams serve effective system specifications for communicating the system operations to participants of different disciplines as well as the system model for the design and development of KSCS.

Delay control and parallel admission algorithms for real-time anycast flow

An anycast flow is a flow that can be connected to any one of the members in a group of designated (replicated) servers (called anycast group). In this paper, we derive a set of formulas for calculating the end-to-end delay bound for the anycast flows and present novel admission control algorithms for anycast flows with real-time constraints. Given such an anycast group, our algorithms can effectively select the paths for anycast flows' admission and connection based on the least end-to-end delay bounds evaluated. We also present a parallel admission control algorithm that can effectively calculate the available paths with a short delay bound for different destinations in the anycast group so that a best path with the shortest delay bound can be chosen.

Malware variant detection using similarity search over sets of control flow graphs

Static detection of polymorphic malware variants plays an important role to improve system security. Control flow has shown to be an effective characteristic that represents polymorphic malware instances. In our research, we propose a similarity search of malware using novel distance metrics of malware signatures. We describe a malware signature by the set of control flow graphs the malware contains. We propose two approaches and use the first to perform pre-filtering. Firstly, we use a distance metric based on the distance between feature vectors. The feature vector is a decomposition of the set of graphs into either fixed size k-sub graphs, or q-gram strings of the high-level source after decompilation. We also propose a more effective but less computationally efficient distance metric based on the minimum matching distance. The minimum matching distance uses the string edit distances between programs' decompiled flow graphs, and the linear sum assignment problem to construct a minimum sum weight matching between two sets of graphs. We implement the distance metrics in a complete malware variant detection system. The evaluation shows that our approach is highly effective in terms of a limited false positive rate and our system detects more malware variants when compared to the detection rates of other algorithms.

Promoting healthy eating, active play and sustainability consciousness in early childhood curricula, addressing the Ben10™ problem: a randomised control trial

Background: This paper details the research protocol for a study funded by the Australian Research Council. An integrated approach towards helping young children respond to the significant pressures of ‘360 degree marketing’ on their food choices, levels of active play, and sustainability consciousness via the early childhood curriculum is lacking. The overall goal of this study is to evaluate the efficacy of curriculum interventions that educators design when using a pedagogical communication strategy on children’s knowledge about healthy eating, active play and the sustainability consequences of their toy food and toy selections. Methods/Design: This cluster-randomised trial will be conducted with 300, 4 to 5 year-old children attending pre-school. Early childhood educators will develop a curriculum intervention using a pedagogical communication strategy that integrates content knowledge about healthy eating, active play and sustainability consciousness and deliver this to their pre-school class. Children will be interviewed about their knowledge of healthy eating, active play and the sustainability consequences of their food and toy selections. Parents will complete an Eating and Physical Activity Questionnaire rating their children’s food preferences, digital media viewing and physical activity habits. All measures will be administered at baseline, the end of the intervention and 6 months post intervention. Informed consent will be obtained from all parents and the pre-school classes will be allocated randomly to the intervention or wait-list control group. Discussion: This study is the first to utilise an integrated pedagogical communication strategy developed specifically for early childhood educators focusing on children’s healthy eating, active play, and sustainability consciousness. The significance of the early childhood period, for young children’s learning about healthy eating, active play and sustainability, is now unquestioned. The specific teaching and learning practices used by early childhood educators, as part of the intervention program, will incorporate a sociocultural perspective on learning; this perspective emphasises building on the play interests of children, that are experienced within the family and home context, as a basis for curriculum provision. Trial Registration: Australian New Zealand Clinical Trials Registry ACTRN12614000363684: Date registered: 07/04/2014

Control flow-based malware variant detection

Static detection of malware variants plays an important role in system security and control flow has been shown as an effective characteristic that represents polymorphic malware. In our research, we propose a similarity search of malware to detect these variants using novel distance metrics. We describe a malware signature by the set of control flowgraphs the malware contains. We use a distance metric based on the distance between feature vectors of string-based signatures. The feature vector is a decomposition of the set of graphs into either fixed size k-subgraphs, or q-gram strings of the high-level source after decompilation. We use this distance metric to perform pre-filtering. We also propose a more effective but less computationally efficient distance metric based on the minimum matching distance. The minimum matching distance uses the string edit distances between programs' decompiled flowgraphs, and the linear sum assignment problem to construct a minimum sum weight matching between two sets of graphs. We implement the distance metrics in a complete malware variant detection system. The evaluation shows that our approach is highly effective in terms of a limited false positive rate and our system detects more malware variants when compared to the detection rates of other algorithms. © 2013 IEEE.

Nonlinear backstepping controller design for sharing active and reactive power in three-phase grid-connected photovoltaic systems

In this paper, a nonlinear backstepping controller is designed for three-phase grid-connected solar photovoltaic (PV) systems to share active and reactive power. A cascaded control structure is considered for the purpose of sharing appropriate amount of power. In this cascaded control structure, the dc-link voltage controller is designed for balancing the power flow within the system and the current controller is designed to shape the grid current into a pure sinusoidal waveform. In order to balance the power flow, it is always essential to maintain a constant voltage across the dc-link capacitor for which an incremental conductance (IC) method is used in this paper. This approach also ensures the operation of solar PV arrays at the maximum power point (MPP) under rapidly changing atmospheric conditions. The proposed current controller is designed to guarantee the current injection into the grid in such a way that the system operates at a power factor other than unity which is essential for sharing active and reactive power. The performance of the proposed backstepping approach is verified on a three-phase grid-connected PV system under different atmospheric conditions. Simulation results show the effectiveness of the proposed control scheme in terms of achieving desired control objectives.

Fun, flow, and fitness: opinions for making more effective active videogames

Despite active videogames' popularity and ability to increase a player's energy expenditure, research indicates their use sharply declines over time, which limits their utility in promoting physical activity. A frequent criticism is that a player's interest is quickly exhausted. At the preconference of the International Society of Behavioral Nutrition and Physical Activity 2014, a group of investigators and videogame developers gathered to share lessons learned from using serious videogames in health behavior change and offer insight to guide future efforts.

State sovereignty and migration control: the ultimate act of discrimination?

Nations zealously guard their borders and carefully vet migrants. This consigns many people to live in states not of their choice and often diminishes their opportunities and their level of flourishing. In some cases it is the difference between life and death. The practice of imposing migration controls is discriminatory. In fact it is the ultimate form of discrimination: 'super-discrimination.' There is no logical or moral reason why non-nationals of a state should not have the same opportunities and freedoms as nationals in that state. One of the most common forms of discrimination is race - treating a person differently simply because of their place of birth. This is one of the clearest and most repugnant forms of discrimination because the location where a person is born is of course merely a happy or unhappy circumstance over which the individual has no control. An accident of birth should not qualify a person for extra privileges or opportunities. The world is a fairer place if to the maximum extent possible luck is taken out of the process for allocating benefits and burdens - which ought to be distributed on the basis of merit and dessert. This paper examines whether there are sound reasons for restricting the flow of world-wide people movement. The main arguments in favour of this policy, relating to security and national building, are ultimately flawed. This exposes a tragic irony given the great efforts that many Western states - which typically have the strongest migration controls - make to stamp out discrimination at the domestic level, and the vast array of international law anti-discrimination instruments, loudly trumpeted by Western nations. This is hypocrisy nearing its finest. The substratum of sovereign states upon which available international law is built is inherently discriminatory and in fact is probably responsible for more harm as a result of the innately discriminatory immigration policies than results from the cumulative operation of all domestic discrimination. The world should move towards loosening migration controls. This would have an enormous number of humanistic benefits, not the least of which is largely eradicating world hunger and poverty.

Thermal control of high pressure die casting using computational fluid dynamics

The quality of high pressure die castings is a function of many interdependent parameters. It has been observed that many defects detected in the HPDC castings can be tracked back to poor die temperature distribution in the critical areas. It has therefore been recommended that the development of a technique to directly control the critical features - making them less sensitive to thermal related parameters - be very beneficial to the HPDC industry. From the information obtained from thermal image (processing), computational fluid dynamics has been applied to design the layout of internal cooling system and assign the flow conditions such as flow rate and pressure of the cooling water. it is observed that CFD prediction provides an excellent insight into the thermal balance of the high pressure die casting.

Transport of cryptotanshinone, a major active triterpenoid in Salvia miltiorrhiza Bunge widely used in the treatment of stroke and Alzheimers disease, across the blood-brain

Cryptotanshinone (CTS), a major constituent from the roots of Salvia miltiorrhiza (Danshen), is widely used in the treatment of coronary heart disease, stroke and less commonly Alzheimer's disease. Our recent study indicates that CTS is a substrate for Pglycoprotein (PgP/MDR1/ABCB1). This study has investigated the nature of the brain distribution of CTS across the brain-blood barrier (BBB) using several in vitro and in vivo rodent models. A polarized transport of CTS was found in rat primary microvascular endothelial cell (RBMVEC) monolayers, with facilitated efflux from the abluminal side to luminal side. Addition of a PgP (e.g. verapamil and quinidine) or multi-drug resistance protein 1/2 (MRP1/2) inhibitor (e.g. probenecid and MK-571) in both luminal and abluminal sides attenuated the polarized transport. In a bilateral in situ brain perfusion model, the uptake of CTS into the cerebrum increased from 0.52 ± 0.1% at 1 min to 11.13 ± 2.36 ml/100 g tissue at 30 min and was significantly greater than that of sucrose. Co-perfusion of a PgP/MDR1 (e.g. verapamil) or MRP1/2 inhibitor (e.g. probenecid) significantly increased the brain distribution of CTS by 35.1-163.6%. The brain levels of CTS were only about 21% of those in plasma, and were significantly increased when coadministered with verapamil or probenecid in rats. The brain levels of CTS in rats subjected to middle cerebral artery occlusion and rats treated with quinolinic acid (a neurotoxin) were about 2- to 2.5-fold higher than the control rats. Moreover, the brain levels in mdr1a(-/-) and mrp1(-/-) mice were 10.9- and 1.5-fold higher than those in the wild-type mice, respectively. Taken collectively, these findings indicate that PgP and Mrp1 limit the brain penetration of CTS in rodents, suggesting a possible role of PgP and MRP1 in limiting the brain penetration of CTS in patients and causing drug resistance to Danshen therapy and interactions with conventional drugs that are substrates of PgP and MRP1. Further studies are needed to explore the role of other drug transporters in restricting the brain penetration of CTS and the clinical relevance.