Left Idle Research Articles

Optimal Scheduling in the Multiserver-job Model under Heavy Traffic

Multiserver-job systems, where jobs require concurrent service at many servers, occur widely in practice. Essentially all of the theoretical work on multiserver-job systems focuses on maximizing utilization, with almost nothing known about mean response time. In simpler settings, such as various known-size single-server-job settings, minimizing mean response time is merely a matter of prioritizing small jobs. However, for the multiserver-job system, prioritizing small jobs is not enough, because we must also ensure servers are not unnecessarily left idle. Thus, minimizing mean response time requires prioritizing small jobs while simultaneously maximizing throughput. Our question is how to achieve these joint objectives. We devise the ServerFilling-SRPT scheduling policy, which is the first policy to minimize mean response time in the multiserver-job model in the heavy traffic limit. In addition to proving this heavy-traffic result, we present empirical evidence that ServerFilling-SRPT outperforms all existing scheduling policies for all loads, with improvements by orders of magnitude at higher loads. Because ServerFilling-SRPT requires knowing job sizes, we also define the ServerFilling-Gittins policy, which is optimal when sizes are unknown or partially known.

PHYSICAL EDUCATION TUTORS PERCEPTIONS OF THE USE OF TECHNOLOGICAL TOOLS FOR REMOTE TEACHING DURING COVID 19

The emergence of the Covid-19 pandemic created the need for the use of dissimilar remote teaching methods and strategies in many subject areas including Physical Education (PE). While this was somewhat successful in developed countries, little is known about the use of technological tools to deliver PE lessons online in developing countries. This study examined the perceptions and experiences of colleges of education PE tutors in adopting technological tools for remote teaching during the Covid-19 pandemic. Semi-structured interviews were used to collect data from 12 tutors (4 females and 8 males) in Ghana. Content analysis was employed as the tool for the analysis of the data. Based on the results, the PE tutors perceived that accessibility was a major challenge to the successful teaching of practical PE lessons online. The tutors further posited that they were motivated to deliver practical lessons online because of the Covid-19 pandemic as they don’t want students to be left idle. In furtherance, the participants recommended Transforming Teaching, Education and Learning and colleges’ management for assisting them to participate in an online course and providing them with ICT support and data. Again, the participants agreed that they prefer face-to-face to online lessons as the latter do not promote socialisation, develop only the cognitive domain and even certificates acquired online are not given due recognition. It is recommended that theory lessons should be held online while face-to-face interaction is better for practical lessons in PE due to accessibility issues connected to poor internet connectivity and difficulty in performing some of the skills online.

Blockchain zakat: An integrated financial inclusion strategy to manage Indonesia’s potential zakat funds

The research aims to analyze the potential of using blockchain to promote integrated financial inclusion through Indonesian potential zakat funds. We use a qualitative approach (the business model canvas) as the analysis tool. We generate the data using the literature study. The essence of the zakat funds management implies that zakat assets should not be left idle. Further, greater zakat funds collected, managed, and distributed will deliver more benefits to mauquf alayh, greater divine rewards to the wakif, and greater funds received by nazir. Our results indicate that the zakat blockchain programs offer various benefits because blockchain facilitates more decentralized and borderless transactions. The benefits include achieving targets more effectively; avoiding overlap; developing zakat more systematically; monitoring more effectively in planning, organizing, actuating, and evaluating nazhir zakat; and contributing to short, medium, and long-term national socioeconomic objectives. In sum, we conclude that more decentralized and borderless blockchain-facilitated transactions potentially enhance Indonesian zakat funds' potential collection and utilization.

Age of Information Minimization for an Energy Harvesting Cognitive Radio

Age of information (AoI) is a performance metric that measures the timeliness and freshness of information, and is particularly relevant in applications with time-sensitive data. This paper studies average AoI minimization in cognitive radio energy harvesting communications. More specifically, the system studied has a primary user with access rights to spectrum, and a secondary user who can utilize the spectrum only when it is left idle by the primary user. The secondary user is an energy harvesting sensor that harvests ambient energy with which it performs spectrum sensing and status updates of its sensing data to a destination. The status-updates are sent by opportunistically accessing the primary user’s spectrum. The secondary user aims to minimize the average AoI by adaptively making sensing and update decisions based on its energy availability and the availability of the primary spectrum with either perfect or imperfect spectrum sensing. The sequential decision problems are formulated as partially observable Markov decision processes and solved by dynamic programming for finite and infinite horizon. The properties of the optimal sensing and updating policies are investigated and shown to have threshold structure. Numerical results are presented to confirm the analytical findings.

Ambiguous Statute Leads to Differing Decisions

An ambiguously worded state law denied penalty fees to a contractor that was left idle by a city's indecisiveness.

An Essential Service in Penrose's Economies of Growth

1. IntroductionEdith T. Penrose's (1914-1996) The Theory of the Growth of the Firm (Penrose, 1959, 1980, 1995, 2009) is an economics classic. This book went on to become foundation in the field of strategic management, when the resource-based view (RBV) appeared in the mid-1980s. RBV is an attempt to explain the creation, preservation, and regeneration of firm's competitive advantage by combining the properties of resources and its transformation.In 1984, we have two noteworthy papers on RBV-Wernerfelt (1984) and Rumelt (1984)-both of which cited Penrose (1959) and were followed by countless significant studies on RBV. Penrose (1959) became known as the shared source of RBV, having advocated the view that companies are essentially pool of resources, whose utilization is organized by the administrative that different companies use their resources in different ways, and even the same types of resources can provide different types of services depending on the company.However, although this interpretation of Penrose (1959) was plausible, it does not explain why Penrose titled her book The Theory of the Growth of the Firm in the first place. The key to understanding Penrose (1959) is the concept of economies of growth. This paper hypothesizes that the economies of growth occur where there are unused start-up expert managerial services.2. Unused Services in OperationFirst, Penrose (1959) assumes that the company is more than simple administrative unit. Penrose focuses on productive resources, including human resources such as managers, and defines the company as a pool of resources the utilization of which is organized in an administrative framework (Penrose, 1959, p. 149). However, even though the company is viewed as collection of productive resources, strictly speaking, the production processes of inputs are not the resources themselves (material and human resources), but the services that the resources render. While resources can essentially be defined independently of their use, services cannot be so defined because the word service implies function or an activity (Penrose, 1959, p. 25). This is the major difference between resources and services. Furthermore, unlike resources, services cannot be stocked; they function well only when they are used frequently. This distinguishing characteristic of services is fundamental pillar of the economies of growth.As long as there are resources not being fully used in current operations, the company has an incentive to look for ways to make full use of those resources to avoid having them left idle. In reality, company's internal inducements to expansion are mainly caused by unused productive services, resources, or special knowledge. The unused services do not often exist in the open form of idle man-hours, but rather in the concealed form of unused abilities (Penrose, 1959, p. 54). The existence of these unused productive services is waste; but they are free even if used profitably, that is, if they can be put to good use, they give the company competitive advantage (Penrose, 1959, pp. 67-68).3. It's Not Economies of Size, but Economies of GrowthWhat are economies of growth when considering this concept as an independent notion of economies of size? First, economies of size, according to Penrose, is the idea that larger company is able to introduce higher volume or new products into the market more effectively than smaller company simply due to its size (economies of size of expansion), and produce and sell products and services more effectively than smaller company simply due to its size (economies of size of operation).The economies of size of expansion (a) relate only to the cost of effecting an expansion; (b) exist if production can begin at lower average cost simply because of size; (c) include the cost of establishing smooth operation for additional production and the cost of enlarging or creating the market for the additional product as part of the production start-up costs. …

Hybrid Rendering with Scheduling under Uncertainty.

As scientific data of increasing size is generated by today's simulations and measurements, utilizing dedicated server resources to process the visualization pipeline becomes necessary. In a purely server-based approach, requirements on the client-side are minimal as the client only displays results received from the server. However, the client may have a considerable amount of hardware available, which is left idle. Further, the visualization is put at the whim of possibly unreliable server and network conditions. Server load, bandwidth and latency may substantially affect the response time on the client. In this paper, we describe a hybrid method, where visualization workload is assigned to server and client. A capable client can produce images independently. The goal is to determine a workload schedule that enables a synergy between the two sides to provide rendering results to the user as fast as possible. The schedule is determined based on processing and transfer timings obtained at runtime. Our probabilistic scheduler adapts to changing conditions by shifting workload between server and client, and accounts for the performance variability in the dynamic system.

Cool Season Invasive Grasses in Northern Great Plains Natural Areas

Native prairie sites within the Northern Great Plains are being invaded by cool season invasive grasses despite utilizing even the most conservation-oriented management. Native prairie sites of the Knife River Indian Villages National Historic Site, located near the confluence of the Knife and Missouri Rivers in central North Dakota, were reassessed 23 years after the first assessment. The native prairie sites were initially assessed the summer of 1984 utilizing a modified Daubenmire technique which entailed randomly placing twenty-five ¼ m2 quadrats along transects at each native prairie site. Prior to 1976, native prairie sites were grazed by livestock; and after the National Park Service took ownership, sites were not grazed by livestock and were essentially left idle. The same technique was repeated during the summer of 2007 on the same native prairie sites surveyed in 1984, and comparisons were made between species composition of those sites in 1984 and 2007. Species composition of several sites across the landscape changed from containing a high percentage of native graminoids and forbs to containing a high percentage of invasive species such as smooth brome (Bromus inermis Leyss.) and Kentucky bluegrass (Poa pratensis L.). A few of the more xeric native prairie sites maintained a high percentage of native graminoids and forbs with minor changes in coverage. This study illustrates the emergence of invasive species and species composition changes under historic land use and climatic conditions and the roles that disturbances, such as grazing processes and fire, may play in maintaining native plant communities.

Determinants of Smallholders’ Decisions to Leave Land Fallow: The Case of Kosovo

AbstractThis article investigates why farmers in Kosovo leave land fallow when their farms’ total land area is small and households, almost fully dependent on farming for their livelihoods, are large. It uses a comprehensive survey carried out during the agricultural year 2005/2006 to explore agricultural households’ perceptions of production, market conditions and general security 6 years after the end of the military conflict in the former Yugoslavia. Several locational, household and farm characteristics empirically approximate the significance of different factors for the amount of land left idle. Two different econometric models are used to address the characteristics of the dependent variable distribution by accounting for endogeneity. The main determinants of the share of land left fallow are found to be related to the economic and institutional structure, and to the general feeling of insecurity.

The impact of decoupled payments on the cost of operating capital

PurposeThe purpose of this paper is to investigate how decoupled direct payments, paid to farm operators based on historical yields and base acreage, may lead to production distortions by altering a farmer's access to credit or enabling the farmer to receive more favorable credit terms. The authors estimate the impact of decoupled direct payments under the 2002 Farm Bill on the credit terms of farm operators, specifically the interest rate on short‐term operating loans. If farm operators are able to obtain more favorable credit terms and reduce their operating cost, then this offers an additional mechanism through which decoupled payments may distort current production.Design/methodology/approachThe authors estimate the impact of decoupled direct payments on the interest rate on short‐term operating loans. In the analysis, the authors control for farm financial characteristics, farm operator characteristics, and other factors. Data from the Agricultural Resource Management Survey for the years 2005‐2007, are used in the weighted regression analysis. Jackknifed standard errors are also computed.FindingsAs the proportion of base acres to total operated acres increases it is found that interest rates decline by a small but statistically significant amount. This implies that direct payments lead to lower operating costs through better credit terms.Research limitations/implicationsLower operating costs may in turn allow some farmers to expand production or produce on land that would otherwise be unprofitable to operate and hence left idle. Ultimately, this distorts current production. However, the small magnitude of the authors' results suggests that the reduction in interest rates, though positive, may have limited distortionary impacts.Originality/valueThe paper provides evidence that decoupled payments alter a farm operator's credit terms and hence could lead to current production distortions. The paper contributes to the growing body of research investigating the mechanisms by which decoupled payments have the potential to distort current production.

Perspective: The Brownfield Professional Team

Successful redevelopment of lands with perceived or real contamination and left idle are commonly termed brownfield sites. These sites often require redevelopment that should consider the site's broader social, political, and economic setting. The parcel of land, which can range from a rural community to an urban neighborhood, is part of a larger ecosystem both scientifically and socially. Most of the urban brownfield literature focuses on the loss or underutilization of the property's function and resulting loss in economic value, sometimes neglecting this large social context of the location of the property.

LEASE DEFAULTS AND THE EFFICIENT MITIGATION OF DAMAGES

The traditional law of leases imposed no duty on landlords to mitigate damages in the event of tenant breach, whereas the modern law of leases does. An economic model of leases, in which absentee tenants may or may not intend to breach, shows that the traditional rule promotes tenant investment in the property by discouraging landlord entry. In contrast, the modern rule prevents the property from being left idle by encouraging landlords to enter and re-let abandoned property. The model reflects the historic use of the traditional rule for agricultural leases, where absentee use was valuable, and the emergence of the modern rule for residential leases, where the primary use entails continuous occupation.

Micromorphological properties of salt affected soils in Northeast Thailand

A micromorphological study was carried out on salt affected soils from three locations on erosional terraces overlain by wash and alluvium under tropical savanna climate in Northeast Thailand where salinity problem has been acute. This aimed at providing detailed data for a better agricultural land use planning of the area. Five or six profiles at each location were sampled along a linear traverse that included the soils with highest and lowest levels of salt accumulation. Sixteen soil profiles were described, sampled and analyzed using physio-chemical, optical microscope and scanning electron microscope with energy dispersive spectrometer (SEM/EDS) techniques. The highest salt affected profiles show salt crusts, bare surfaces and halophytic plants and these soils have been left idle. All soils are deep, poorly drained, moderately to highly developed and with various salinity levels. They are fourteen Natraqualfs and two Endoaqualfs. Soil textures are sandy for location 1, clayey for location 2 and with a sandy topsoil and clayey subsoil for location 3. The soils at locations 1 and 2 mostly have high values of electrical conductivity (EC) and exchangeable sodium percentage (ESP). Soils at location 3 may have been affected by desalinization and alkalization as is indicated by low EC, high basic cations and high pH. Field morphology, optical micromorphology and SEM/EDS analysis results show clear accumulation of salt in some profiles. Their microstructures are different due to the difference in their texture. Compact grain and bridge grain structures are common in sandy-textured soil whereas channel and subangular blocky structures are common in the clayey soils. Quartz and runi-quartz grains are common as skeleton materials, but are present in different sizes and amounts. Halite occurs in voids in soils at locations 1 and 2 and is abundant in Pedons 1 and 6 where salt crusts exist. Calcite is present only in one profile (Pedon 1). Amorphous pedofeatures are manganiferrous impregnative nodules and iron and manganese oxide impregnated s-matrix. The EDS spectra indicate the presence of barite (BaSO 4) and sylvite (KCl) crystals in voids in some of the soils. The element composition of the soil matrix in a triangle graph of SiO 2: Al 2O 3: Fe 2O 3 is displaced from the ‘kaolin line’ towards the SiO 2 apex, indicating that very fine-grained quartz and/or a Si-rich clay mineral (s) is present in the matrix. The presence of Si-rich clay minerals is supported by XRD results that identified smectite in addition to kaolin and may be an evidence of the resilication process that can occur in salt affected soils. The data points near the Fe 2O 3 apex of the triangle graphs represent iron oxide nodules and their position on the matrix Al 2O 3/SiO 2 line indicates that induration of the matrix with iron oxide has occurred and that the nodules have formed in situ. The normalized element composition of the matrix in triangle graph between SiO 2: Al 2O 3: Na 2O + CaO + MgO indicates that in some instances the salts of Na, Ca and Mg have indurated the soil matrix as data points for salt-rich matrix fall on the clay matrix composition line.

Increasing Oil Production Through Leasing of Idle Wells

The national oil company of Trinidad and Tobago (Petrotrin) has more than 5,000 idle wells. The company initiated a procedure for leasing these idle wells to small independent operators in July 1989 through a program known as the lease operatorship program. This paper reviews the status of lease operatorship activities, examines the benefits and the strategies adopted by the operators as well as some of the important issues involved, describes the requirements for external operatorship, and outlines planes for the future of the program.

The Use of Field Days in Economic Models of Crop Farms

The time available for the completion of field operations, commonly referred to as field days, is important to the economic efficiency of crop farms. The effects of field days on economical cropping decisions is complicated by the significant variation which occurs in field days from season to season and year to year. This paper discusses the use of field days data in economic models of crop farms. It presents two linear programming models of a midwestern U.S. corn (Zea mays L.) and soybean [Glycine max (L.) Merr.] farm. The first model treats field days deterministically, with known values in each production period. The second model treats field days as random variables, using the technique of discrete stochastic programming. Optimal solutions from the two models are compared to demonstrate the economic impacts of field days variability [...]

Virtual-channel flow control

Network throughput can be increased by dividing the buffer storage associated with each network channel into several virtual channels. Each physical channel is associated with several small queues, virtual channels, rather than a single deep queue. The virtual channels associated with one physical channel are allocated independently but compete with each other for physical bandwidth. Virtual channels decouple buffer resources from transmission resources. This decoupling allows active messages to pass blocked messages using network bandwidth that would otherwise be left idle. The paper studies the performance of networks using virtual channels using both analysis and simulation. These studies show that virtual channels increase network throughput, by a factor of four for 10-stage networks, and reduce the dependence of throughput on the depth of the network. >

Virtual-channel flow control

Network throughput can be increased by dividing the buffer storage associated with each network channel into several virtual channels [DalSei]. Each physical channel is associated with several small queues, virtual channels, rather than a single deep queue. The virtual channels associated with one physical channel are allocated independently but compete with each other for physical bandwidth. Virtual channels decouple buffer resources from transmission resources. This decoupling allows active messages to pass blocked messages using network bandwidth that would otherwise be left idle. Simulation studies show that, given a fixed amount of buffer storage per link, virtual-channel flow control increases throughput by a factor of 3.5, approaching the capacity of the network.

Holding Idle Capacity to Deter Entry

In this JOURNAL, Dixit (I980) carefully analysed the extent to which an established firm facing a prospective entrant might make an investment in capacity beyond that which is optimal for its pre-entry output. In his model, both the established firm and prospective entrants understand that a quantity setting Nash equilibrium would be established in any post-entry game. Dixit showed that Spence (I977) had studied an imperfect equilibrium (that is, an equilibrium that depended upon a threat that was not credible) to obtain his result that firms might hold excess capacity to deter entry. In a perfect equilibrium, a firm would not wish to install capacity that would be left idle if entry did not occur. Dixit's conclusion, however, depends on his assumption that each firm's marginal revenue is always decreasing in the other's output.' This is quite a restrictive assumption. For example it is never satisfied in the relevant range for economists' second-favourite demand curve constant elasticity demand. The basic point is unchanged if the firms anticipate price competition with differentiated products rather thanquantity competition in any post-entry game: Under quite plausible conditions, rational firms facing rational potential entrants may install capacity that will certainly be left idle. We are thus able to rehabilitate Spence's original proposition in a perfect equilibrium setting.

Some problems of stochastic resource allocation

Suppose that a number of jobs are to be carried out by a single processing unit orserver. The server can process any number of jobs at the same time but the time taken to finish all the jobs is the same no matter what scheduling policy is used, provided the server is never left idle. It is, however, possible to minimise the total delays to individual jobs by adopting a suitable policy. Optimal policies are derived here for the situation when the processing times are random variables. If the completion rates (analogous to hazard rates) for every job are increasing it is optimal to process the jobs in sequence. If they are decreasing the optimal policy involves simultaneous processing. These results are applied to a more general resource allocation problem arising in industrial chemical research.

Some problems of stochastic resource allocation

Suppose that a number of jobs are to be carried out by a single processing unit orserver. The server can process any number of jobs at the same time but the time taken to finish all the jobs is the same no matter what scheduling policy is used, provided the server is never left idle. It is, however, possible to minimise the total delays to individual jobs by adopting a suitable policy. Optimal policies are derived here for the situation when the processing times are random variables. If the completion rates (analogous to hazard rates) for every job are increasing it is optimal to process the jobs in sequence. If they are decreasing the optimal policy involves simultaneous processing. These results are applied to a more general resource allocation problem arising in industrial chemical research.