Full Priority Research Articles

Frequency control in an isolated wind‐diesel hybrid system with energy storage and an irrigation water supply system

AbstractWind‐Diesel Hybrid Systems (WDHSs) integrate wind turbines into diesel power systems, reducing costs and emissions in isolated grids. Due to the no‐load consumption of the Diesel Generators (DGs), fuel savings are only possible when the DGs are shut down. This requires a proper implementation of the frequency control to avoid perturbations because of the wind speed variations. During wind‐only (WO) operation, the Synchronous Machine (SM) generates the isolated grid voltage and the frequency controller varies the energy stored/supplied by an Energy Storage System and consumed by the controllable loads to balance the power. In this paper, a Battery‐based Energy Storage System (BESS) uses Li‐Ion batteries with a Dual Active Bridge (DAB) and a grid‐tie inverter connected to the isolated network. The controllable load is an Irrigation Water Supply System (IWSS), consisting of a pump supplying water to a reservoir tank. The pump is driven by a variable speed drive that uses a Permanent Magnet Synchronous Motor (PMSM). The coordinated control of BESS and IWSS gives full priority to the BESS for harnessing the wind potential whereas the IWSS consumes the excess of wind power. The full Wind Diesel Power System (WDPS) is modelled and simulated to validate the proposed system for different case scenarios.

A comparison study on responsiveness of three mechanisms to affirmative action in school choice

This note provides a comparison study on responsiveness of three popular mechanisms to affirmative action in school choice. When the exogenous school choice environment gives full priority to the minority, the student-proposing deferred acceptance (DA) mechanism is responsive to both the quota-based and reserve-based affirmative action policies. In comparison with DA mechanism, the top trading cycles (TTC) mechanism is responsive to neither the quota-based nor the reserve-based affirmative action even when the exogenous school choice environment gives full priority to the minority. When each minority student has higher priority than each majority student at each school, the TTC mechanism is responsive to the quota-based affirmative action. However, under the environment as above, the Boston mechanism is not responsive to the quota-based affirmative action.

Spectrum utilization efficiency in CRNs with hybrid spectrum access and channel reservation: A comprehensive analysis under prioritized traffic

The enhancement of spectrum utilization efficiency (SUE) is a critical objective in fifth generation networks-enabled Internet of Things (5G-IoT) for providing communication opportunities to plethora of 5G-IoT devices within the already scarce spectrum. Cognitive radio networks (CRNs) with interweave and underlay modes are foreseen to achieve this objective. The interweave mode is adequate for legacy CRNs, while the underlay mode is fitting for resource-constrained CRNs. As 5G-IoT is rapidly evolving into heterogeneous networks, CRNs enabled by hybrid underlay-interweave mode (H-mode) emerge to be the best option for SUE enhancement in 5G-IoT. In this paper, we comprehensively analyze the performance of H-mode enabled CRNs containing heterogeneous users by proposing two H-mode schemes, namely, primary user full priority (FP) and primary user partial priority (PP). The schemes consider secondary users (SUs) with high and low priorities. In FP, primary users (PUs) have absolute priority in channel access while in PP, SUs with certain attributes are immune from interruptions. Additionally, to accommodate interrupted users, a simple yet efficient channel reservation algorithm is proposed, which divides the given channels into reserved and unreserved bands. Using Markov chain modeling, expressions are derived for core SUE related performance metrics including service completion rate (SCR), blocking probability (BP), network serveability (NS), successful service completion probability (SSCP), handoff probability, and throughput, independently for PUs and all types of SUs. Performance of the proposed schemes is analyzed under varying channel failure rates and network traffic loads. Efficacy of the proposed schemes is shown through analytical and simulation results against state-of-the-art. Improvements of up to 67% in BP and 83% in cost efficiency are recorded as compared to the state-of-the-art. Likewise, up to 10% and 84% difference in PUs’ and SUs’ SSCP, respectively, and up to 17% and 93% difference in PUs’ and SUs’ SCR, respectively, are noted. Similarly, up to 85% performance difference in NS is recorded. Moreover, up to 35% improvement in throughput in H-mode is witnessed. Lastly, handoff probability is found to be increased by 5%.

Conservation issues using discordant taxonomic and evolutionary units: a case study of the American manatee (

The delimitation of evolutionarily significant units (ESUs) frequently results in controversy, but prioritising populations with evolutionary independence is essential for effective in situ conservation management. The American manatee (Trichechus manatus) is distributed along subtropical and tropical coastal waters from Florida (USA) to Alagoas (Brazil), and two subspecies are traditionally recognised, namely, T. m. latirostris, restricted to the Florida peninsula, and T. m. manatus, found in the remaining areas. However, this subspecific classification is not supported by genetic and morphologic evidence, which, rather, recognises two deeply differentiated populations or ESUs called Atlantic (Brazil) and Caribbean (from Venezuela to Florida). In this viewpoint paper, we compare both intraspecific divisions of T. manatus and the conservation implications. First, we used all available mtDNA evidence to test the genealogical clustering of the two American manatee ESUs by using a tree-based coalescent method. Second, we have used different models under a coalescent framework to estimate the historic gene flow among manatee populations. The analysis of the spatial distribution of mtDNA clusters confirmed the existence of the two suggested ESUs, rather than the two claimed subspecies. Furthermore, the best model to explain historic migration indicates that Brazilian manatees belong to an isolated population, whereas Florida and Caribbean populations are connected by more recent gene flow. These results have confirmed that T. manatus of the Caribbean, Gulf of Mexico and Florida belong to the same deme or Caribbean ESU, and the relatively isolated population inhabiting the Atlantic coast of Brazil belongs to the Atlantic ESU. Furthermore, both ESUs are separated by an interspecific hybrid zone (with the Amazonian manatee) located around the mouth of the Amazon River towards the Guianas coastline. The subdivision of two ESUs is also highly supported by karyotypic, morphological and ecological data, and is in clear disagreement with the traditional subspecies designations and the IUCN priorities, which manages Brazilian manatees as part of the Antillean manatee subspecies (T. m. manatus). Rather, Brazilian manatees should be considered as a full priority for conservation and require further taxonomic research; because of their deep history of isolation, they present high genetic and morphologic differentiation from all other American manatees.

Invite Your Friend and You’ll Move Up in Line: Optimal Design of Referral Priority Programs

Problem definition : This paper studies the optimal design of referral priority programs, in which customers on a waiting list can jump the line by inviting their friends to also join the waiting list. Academic/practical relevance : Recent years have witnessed a growing presence of referral priority programs as a novel customer-acquisition strategy for firms that maintain a waiting list. Different variations of this scheme are seen in practice, raising the question of what should be the optimal referral priority mechanism. Methodology : I build an analytical model that integrates queuing theory into a mechanism design framework in which the objective of the firm is to maximize the system throughput, that is, accelerate customer acquisition as much as possible. Results : My analysis shows that the optimal mechanism has one of the following structures: full priority; partial priority; first in, first out (FIFO); and strategic delay. A full-priority (partial-priority) scheme enables referring customers to get ahead of all (only some) nonreferring ones. A FIFO scheme does not provide any priority-based referral incentive. A strategic-delay scheme grants full priority to referring customers but artificially inflates the delay of nonreferring ones. I show that FIFO is optimal if either the base-market size or the referral cost is large. Otherwise, partial priority is optimal if the base-market size is above a certain threshold; full priority is optimal at the threshold base-market size; strategic delay is optimal if the base-market size is below the threshold. I also find that referrals motivate the firm to maintain a larger capacity and therefore can surprisingly shorten the average delay, even though more customers sign up and strategic delay is sometimes inserted. Managerial implications : My paper provides prescriptive guidance for launching an optimal referral priority program and rationalizes common referral schemes seen in practice.

Analysis of Trams’ Consumption Depending on the Type of Traffic Light Used

In the XXI century, when environmental awareness is growing and the impact of human activity on the planet is more and more noticeable, striving to minimize energy consumption seems to be a necessary direction in the development of technology. This development cannot take place without an initial understanding and describing the relationships influencing specific technologies. It also needs empirical verification of assumed theories. Modern trams play an important role in the functioning of urban transport. Being one of the oldest modes of environmentally friendly transport, in European capitals they are currently perceived as one of the most convenient means of transport. This is due, among other things, to the high velocity of transport along the route. The energy consumed by trams indirectly depends on the driving characteristics, i. e. speed, acceleration and stops on the route, which are also caused by stopping at traffic light controlled junctions. This paper presents the results of an experiment showing the change in the level of electric energy consumption depending on the applied method of traffic light control. This article presents the conditions influencing the power consumption in trams, describes the possible strategies of traffic lights control and their consequences for other traffic participants. The research was carried out in real conditions in everyday traffic, measuring the level of electricity consumption in case of both fixed-time and actuated signaling with full priority for trams. On the examined section there were both modern asynchronous-drive as well as traditional resistor-drive vehicles. The conclusions drawn from the survey confirm the validity of introducing modern solutions and may be useful for estimating investment costs.

Responsive affirmative action in school choice: A comparison study

This note provides a comparison study on responsiveness of two extensively used mechanisms to affirmative action in school choice. For priority-based affirmative action, we show that, if a stronger priority-based affirmative action favors minority students by giving full priority to the minority, then such a policy makes each minority student weakly better off under the student-proposing deferred acceptance (henceforth, DA) mechanism. However, the top trading cycles (henceforth, TTC) mechanism does not satisfy this property. Under the DA mechanism, if the original problem gives full priority to the minority, then the assignment of minority students does not change when the problem moves to a higher level of affirmative action. On the contrary, this property does not hold under the TTC mechanism.

Prioritization of Overflow Tasks to Improve Performance of Mobile Cloud

Mobile devices may offload their applications to a virtual machine running on a cloud host. This application may fork new tasks which require virtual machines of their own on the same physical machine. Achieving satisfactory performance level in such a scenario requires flexible resource allocation mechanisms in the cloud data center. In this paper we present two such mechanisms which use prioritization: one in which forked tasks are given full priority over newly arrived tasks, and another in which a threshold is established to control the priority so that full priority is given to the forked tasks if their number exceeds a predefined threshold. We analyze the performance of both mechanisms using a Markovian multiserver queueing system with two priority levels to model the resource allocation process, and a multi-dimensional Markov system based on a Birth-Death queueing system with finite population, to model virtual machine provisioning. Our performance results indicate that the threshold-based priority scheme not only performs better, but can also be tuned to achieve the desired performance level.

Welfare egalitarianism with other-regarding preferences

We consider the problem of dividing a perfectly divisible good among individuals who have other-regarding preferences. Assuming no legitimate claims and purely ordinal preferences, how should society measure social welfare so as to satisfy basic principles of efficiency and fairness? In a simple model of average externalities, we characterize the class of social preferences which give full priority to the individual with the lowest egalitarian equivalent.

Secured credit and partial priority: Corporate finance as a creation or an externalisation practice?

AbstractFour developments warrant revisiting the debate on full priority and taking steps to implement a partial priority system. The first development is that secured credit increasingly results in a complete lack of funds to cover the expenses of the insolvency procedure. The second development is that secured credit is often not doing what the proponents of full priority argue that it is doing, namely facilitating growth. Instead, it is increasingly used to simply facilitate the leverage of the company without any intent to invest in the company. Thirdly, the plight of unsecured creditor is deteriorating in new ways. Trade creditors in particular are increasingly forced into the position of being suppliers of credit, turning non-adjusting creditors into what can be referred to as adjustable creditors. The fourth development is that these trade creditors find insolvency laws increasingly working against them instead of for them.

Invite Your Friend and You’ll Move Up in Line: Optimal Design of Referral Priority Programs

This paper studies the optimal design of referral priority programs, in which customers on a waitlist can jump the line by inviting their friends to also join the waitlist. Recent years have witnessed a growing presence of referral priority programs as a novel customer acquisition strategy for firms that maintain a waitlist. Different variations of this scheme are seen in practice, raising the question of what should be the optimal referral priority mechanism. We build an analytical model that integrates queueing theory into a mechanism design framework, where the objective of the firm is to maximize the system throughput, i.e., to accelerate customer acquisition as much as possible. Our analysis shows that the optimal mechanism has one of the following structures: full-priority, partial priority, first-in-first-out (FIFO), and strategic delay. A full-priority (partial-priority) scheme enables referring customers to get ahead of all (only some) non-referring ones. A FIFO scheme does not provide any priority-based referral incentive. A strategic-delay scheme grants full priority to referring customers, but artificially inflates the delay of non-referring ones. We show that FIFO is optimal if either the base market size or the referral cost is large. Otherwise, partial priority is optimal if the base market size is above a certain threshold; full priority is optimal at the threshold base market size; strategic delay is optimal if the base market size is below the threshold. We also find that referrals motivate the firm to maintain a larger capacity and therefore, can surprisingly shorten the average delay even though more customers sign up and strategic delay is sometimes inserted. Our paper provides prescriptive guidance for launching the optimal referral priority program and rationalizes common referral schemes seen in practice.

Secured Credit and Partial Priority: Corporate Finance as a Creation or an Externalisation Practice?

Four developments warrant revisiting the debate on full priority and taking steps to implement a partial priority system. The first development is that secured credit increasingly results in a complete lack of funds to cover the expenses of the insolvency procedure. The second development is that secured credit is often not doing what the proponents of full priority argue that it is doing, namely facilitating growth. Instead, it is increasingly used to simply facilitate the leverage of the company without any intent to invest in the company. Thirdly, the plight of unsecured creditor is deteriorating in new ways. Trade creditors in particular are increasingly forced into the position of being suppliers of credit, turning non-adjusting creditors into what can be referred to as adjustable creditors. The fourth development is that these trade creditors find insolvency laws increasingly working against them instead of for them.

The Floating Charge is Dead; Long Live the Floating Charge -- A Canadian Perspective on the Reform of Personal Property Securities Law

This paper assesses the impact and implications of the death of floating charge theory in PPSA regimes on the priority status of the first in time all assets security holder. I focus on two classes of creditors' claims to which the floating charge has traditionally been vulnerable: subsequent purchase money security interests (PMSIs) and subsequent unsecured and preferential creditors. As we shall see, PPSA reform has greatly strengthened the position of the floating chargee, a trend which has provoked an intensive re-examination of the policy merits of full priority for secured creditors generally. In the conclusion, I summarise the case for preserving the functional premise underpinning the equitable institution of the floating charge in the pursuit of statutory reform. This was the hope m ill-founded as will be seen -- that the traditional vulnerability of the floating chargee to subordination to pre-crystallization creditors would provide the holder of an all assets security interest with a significant incentive to monitor the debtor's dealings with circulating collateral and to intervene to terminate a financially troubled debtor's business operations in a timely fashion.

Street Network Design for a Sustainable Mobility System

An urban network's shape and characteristics can have high influence on many mobility aspects, such as travel distance, mode choice and safety. For example, can a tram be a real competition to the car? Definitely yes if the car is stuck in a traffic jam and the tram has priority, but not only in such case! With a proper system design a tram may offer a faster travel to the city centre than the car. On the other hand if the tram provides faster travel than the car only during several peak hours, it is usually enough to provide better service for a majority of people travelling in such direction.For intense on-street public transport networks full priority is not always possible. This is another reason to resign from a paradigm of providing public transport along major car arteries – the urban public transport will be more efficient, also in speed terms, when it will be closer to commuters. Such closeness means a decrease in segregation, so part of the paper will be dedicated to theoretical calculations and practical observations of allowable tram and bus speeds on city streets.Safety leads to a problem of homogeneity of streets’ technical class and of coherence between streets’ functional and technical classes. Data from both Poland and other countries shows, that such elements as traffic intensity and extend of traffic segregation should strictly coincide with proper technical parameters. It is problematic, since many European streets, for historical reasons, cannot be rebuilt to fully meet uniform standards of one class, so results of inquiries on how to make these standards adjustable without compromising safety or living quality will be presented.Concluding, the aim of this paper is to gather experience gained from theoretical calculations and practical designs, and present a street network as a system. A system that properly implemented allows for sustainable, efficient and safe mobility. A system that to some extend is adjustable to local historical conditions. A system that, unfortunately due to local pressure and political reasons, is often overridden, with sober consequences. The investigations were focused on specific locations, but strengthened with theoretical calculations and generalised allowing for wide implementations.

Welfare Egalitarianism with Other-Regarding Preferences

We study the fair allocation of a one-dimensional and perfectly divisible good when individuals have other-regarding preferences. Assuming no legitimate claims and purely ordinal preferences, how should society measure social welfare so as to satisfy basic principles of efficiency and fairness? We define the egalitarian equivalent as the size of the egalitarian allocation which leaves the individual indifferent to the current allocation. In two simple models of average and positional externalities, we characterize the class of social preferences which give full priority to the individual with the lowest egalitarian equivalent in the economy.

Investigating freeway traffic hypercongestion between an on-ramp and its immediate upstream off-ramp

This paper applies the freeway traffic congestion dynamics proposed in Laval and Leclercq [2010. “Continuum Approximation for Congestion Dynamics Along Freeway Corridors.” Transportation Science 44 (1): 87–97] but with a modified distribution scheme of freeway merging flows to investigation of traffic hypercongestion on a freeway between an on-ramp and its immediate upstream off-ramp. The reason to make this modification is that the original merging scheme of this dynamics is found to possibly give undesired full priority to the traffic from the on-ramp and also occasionally make the resulting flow going through the merge greater than the available capacity. Traffic hypercongestion in this paper refers to a state where speed and flow change in the same direction as density varies. A homogeneous freeway segment chosen for this investigation includes an on-ramp and an off-ramp, which may correspond to a freeway passing by a city or town, with an off-ramp lying upstream towards the city and an on-ramp downstream. The entry flow from the upstream approach of the freeway was fixed and constant within the time horizon while both deterministic and random on-ramp inflow rates were used in this investigation. Then the formation and dissipation of traffic hypercongestion is investigated as on-ramp demand and off-ramp departure profiles vary. The first finding of this investigation is that the density in the hypercongestion area behind the merge never reached the jam density. Second, the hypercongested area continued to grow as long as the sum of the demand from the upstream of the freeway and that from the on-ramp was greater than the available capacity at the merge. Third, as long as the rate of flow leaving from the freeway via the off-ramp was not smaller than the entry flow rates from the on-ramp, no hypercongestion had been observed. In addition, in analysing the numerical results, a series of discussions was carried out to build the linkage between the on- and off-ramp flow profiles and the generated and attracted demand of the city plus its adjacent area the two ramps served for; these discussions suggest that the balanced generated and attracted demand of the city plus its adjacent area can reduce or even remove traffic hypercongestion behind the merge on the chosen freeway segment.

Violência sexual intrafamiliar contra crianças e adolescentes: entre a prevenção do crime e do dano

OBJETIVOS: compreender as representações sociais de membros do Poder Judiciário acerca da prevenção da violência sexual intrafamiliar contra crianças e adolescentes. MÉTODOS: pesquisa de abordagem qualitativa que teve como campo de estudo as 1ª e 2ª Varas dos Crimes contra a Criança e o Adolescente, no Tribunal de Justiça de Pernambuco, com participação de 17 sujeitos (juiz, assessor, técnicos e analistas judiciários). Observação participante, entrevistas semiestruturadas e grupo focal compreenderam as técnicas para coleta de dados, que foram analisados por meio da interpretação dos sentidos. RESULTADOS: a categoria "cultura penal" emergiu dos discursos, bem como suas subcategorias: "prevenção do crime" e "prevenção do dano". CONCLUSÕES: as representações dos sujeitos revelam uma dicotomia, caracterizando o conflito entre a tradição do Poder Judiciário e o direito novo, que abrange os princípios da proteção integral e da prioridade absoluta às crianças e dos adolescentes. O conceito de prevenção da violência sexual intrafamiliar contra crianças e adolescentes deve ser ampliado para além da mera prevenção do crime. A abordagem do problema por meio da prevenção requer que se incorpore ao Poder Judiciário uma cultura penal que abarque os princípios da proteção integral e da prioridade absoluta.

Judiciary as the last resort to protect children and adolescents: intersectoral actions, investment in human resources, and structuring of services

This study aimed to identify the work developed by the Judiciary to prevent sexual violence against children and adolescents within the family. The approach to social representations in a cultural perspective was used. The field study consisted in the 1st and 2nd Court of Crimes against Children and Adolescents, at the State Supreme Court of Pernambuco, Brazil. Participant observation, semi-structured interviews, and focus group with 17 subjects were the techniques for data collection, analyzed through the interpretation of meanings, allowing the identification of the category "The Judiciary as the ultimate level" and the following subcategories: "The public policies to prevent violence" and "The structure and dynamics of Courts". This study allows the visualization of the Judiciary's limitations with regard to the full protection and absolute priority, and that the work along with the victims demands investments in structure and human resources.

Iron Cannot Fight1 – The Role of Technology in Current Russian Military Theory

Contemporary Russian military theory is dominated by three schools of thought: the ‘traditionalists’, the ‘modernists’ and the ‘revolutionaries’. On the role of technology in future warfare, the traditionalists argue for both high tech and massive forces at the same time. The modernists are ready to trade manpower for technology, whereas the revolutionaries give technology full priority. Both the traditionalists and the modernists believe Russia, because of the country's technological lag and limited resources, should respond asymmetrically to the Western technology challenge. The revolutionaries, on the other hand, maintain that Russia must respond in kind. If not, the country will no longer be able to defend its sovereignty. The currently ongoing radical reform of the Russian military is a partial victory for the modernists, but which model or mix of models that will dominate in the future is first of all dependent on the Russian military's purchasing power and the state of the domestic defence industry.

The tyranny of non-aggregation versus the tyranny of aggregation in social choices: a real dilemma

Can a tiny gain to sufficiently many well-off justify imposing a much larger sacrifice on the worst-off? We show that if one answers negatively to such a question and endorses replication invariance, one is forced to accept the maximin principle and give full priority to the worst-off even when a tiny gain to the worst-off imposes a substantial sacrifice on arbitrarily many well-off. If one dislikes this consequence, one faces a real dilemma in choosing between the tyranny of aggregation and the tyranny of non-aggregation.