Number Of Commodities Research Articles

On the complexity of stable hypergraph matching, stable multicommodity flow and related problems

In this paper we study stable multicommodity flows, stable hypergraph matchings and some related problems, like the Hospital-Resident-Couple (hrc) problem. We give a simpler proof of the existence of a stable multicommodity flow by reducing it to scarf. We show that finding a stable fractional solution of a hrc or a 3-dimensional stable matching (stable family) instance is PPAD-complete. Then we derive from these results that the Fractional hypergraph matching problem is PPAD-complete even if all hyperedge sizes and vertex degrees are at most 3. Furthermore, we prove that computing stable multicommodity flows is PPAD-complete even if the number of commodities is 3, the sum of in and out degrees is at most 3 at each vertex and all terminals and sources are the same. We also show that deciding if there exists a stable integer multicommodity flow is NP-complete even with only two commodities and similar restrictions.

Multi-period hub location problem: a review

In hub-and-spoke systems, due to the changes in the input parameters affecting the system over time, transportation system providers should make the right and timely decisions about hub facilities. For this reason, multi-period hub location problems are especially important. This paper presents a comprehensive review of multi-period hub location problems from 1990 up to the most recent published studies. First, we study the developed models based on some characteristics: type of planning horizon (continuous-time and discrete-time), capacity constraints (uncapacitated, capacitated, and modular), type of problem (median and covering), type of services (single-level and hierarchical), number of commodities and modes, type of hub facility (mobile and virtual), type of assignment (single and multiple), and type of parameters (deterministic and uncertain). Also, practical applications of the models are investigated. Then, we survey the proposed solution methods and real-life case studies. Finally, future suggestions are presented for researchers.

Examining export advantages in Indian horticulture: an approach based on product mapping and seasonality

PurposeThe present study provides evidence on export advantages of horticultural commodities based on competitiveness, trade balance and seasonality dimensions.Design/methodology/approachThe study delineated horticultural commodities in terms of comparative advantage, examined temporal shifts in export advantages (mapping) and estimated seasonality. Product mapping was carried out using the Revealed Symmetric Comparative Advantage (RSCA) and Trade Balance Index (TBI). Seasonal advantages were examined through a graphical approach along with the objective tests, namely, modified QS-test (QS), Friedman-test (FT) and using a seasonal dummy.FindingsCucumbers/gherkins, onions, preserved vegetables, fresh grapes, shelled cashew nuts, guavas, mangoes, and spices emerged as the most favorable horticultural products. India has a strong seasonal advantage in dried onions, cucumber/gherkins, shelled cashew nut, dried capsicum, coriander, cumin, and turmeric. The untapped potential in horticulture can be addressed by handling the trade barriers effectively, particularly the sanitary and phytosanitary issues, affecting the exports. Proper policies must be enacted to facilitate the investment in advanced agricultural technologies and logistics to ensure the desired quality and cost effectiveness.Research limitations/implicationsCommodity-specific studies on value chain analysis would provide valuable insights into the issues hindering exports and realizing the untapped export potential.Originality/valueThere is no holistic and recent study illustrating the horticulture export advantages covering a large number of commodities in the Indian context. The study would be helpful to the stakeholders for drawing useful policy implications.

Analysis on the Development of Pakancupung Agropolitan Area in Kediri District, Indonesia

Regional economic growth can be expressed as an increase in the number of commodities that can be used or obtained in an area. Meanwhile, regional development is one of the development programs that aim to boost the growth rate of a region. Pakancupung agropolitan area is one of the agropolitan areas in Kediri Regency which has good potential of natural resources to be developed. This study aims at identifying the potential and problems of natural physical factors as well as supporting factors that influence the development of Pakancupung agropolitan area in Kediri regency. This study uses Rapid Assessment approach through several analysis techniques including LQ analysis, Growth Share analysis, Linkage System analysis, Institutional analysis, and Agropolitan Subsystem analysis. The results show that Pakancupung area has 3 commodities, namely rice, chilli and shallot, and the main commodities to be developed are rice, organic rice, shallot, red chilli and catfish. The development of agropolitan area in Pakancupung region has close linkages to other sectors, such as the industrial sector, the trade sector and the tourism sector. Overall, the number of supporting facilities and infrastructure for the agropolitan area at Pakancupung is sufficient. Keywords: Agropolitan, Commodities, Regional Development, LQ Analysis, Growth Share Analysis, Linkage System Analysis DOI: 10.7176/JESD/13-8-02 Publication date: April 30 th 2022

Прогноз рынка сырьевых материалов

The last twenty years have been a favorable period for the global economy. Asian economies grew rapidly, which boosted the demand for key commodities such as gold, copper and iron ore, and increased mining employment worldwide. This growth has been largely driven by the process of globalization and the rising welfare of population in the emerging markets such as China and India. The world is now entering a more dangerous phase of its development, as political and economic tensions between China and the United States are increasing and threaten to nullify the results of the economic progress. A rollback to protectionism and de-globalization may occur. Asia has been the engine of the mining industry, and commodity prices have helped to determine the prospects of the mining cycle. A number of commodities, including copper, have rebounded from their lows in recent months. This suggests that a new phase of economic recovery is starting to gain momentum, opening a new phase in the expansion of the global mining sector.

New partial aggregations for multicommodity network flow problems: An application to the fixed-charge network design problem

When solving hard multicommodity network flow problems using an LP-based approach, the number of commodities is a driving factor in the speed at which the LP can be solved, as it is linear in the number of constraints and variables. The conventional approach to improve the solve time of the LP relaxation of a Mixed Integer Programming (MIP) model that encodes such an instance is to aggregate all commodities that have the same origin or the same destination. However, the bound of the resulting LP relaxation can significantly worsen, which tempers the efficiency of aggregating techniques. In this paper, we introduce the concept of partial aggregation of commodities that aggregates commodities over a subset of the network instead of the conventional aggregation over the entire underlying network. This offers a high level of control on the trade-off between size of the aggregated MIP model and quality of its LP bound. We apply the concept of partial aggregation to two different MIP models for the multicommodity network design problem. Our computational study on benchmark instances confirms that the trade-off between solve time and LP bound can be controlled by the level of aggregation, and that choosing a good trade-off can allow us to solve the original large-scale problems faster than without aggregation or with full aggregation.

Determinants of Tooth Loss in a Medicaid Adult Population.

The objective of this retrospective cohort study is to examine the determinants of tooth loss in a Medicaid-enrolled population using claims data from 2016 to 2018. Deidentified administrative claims data for Medicaid-enrolled adults between the ages of 50 and 90 y in 2016 to 2018 were examined using the IBM Watson MarketScan Medicaid Database. The sample size was 91,468. The entire sample was divided into 2 cohorts: no tooth loss cohort (n = 54,786) and tooth loss cohort (n = 36,682). The tooth loss cohort was further divided into 2 groups: 1 to 5 teeth lost (n = 29,141) and 6 or more teeth lost (n = 7,541). Tooth loss was described by age, gender, race, number of commodities, and if periodontal treatment was performed. Logistic regression models were conducted to examine factors associated with tooth loss. Within the tooth loss cohort, the patients who had periodontal treatment had higher odds of losing at least 1 tooth (odds ratio [OR], 1.15; confidence interval [CI], 1.10-1.20) and lower odds of losing 6 or more teeth (OR, 0.25; CI, 0.22-0.29). In the regression analysis, the predictive margins of tooth loss for 1 tooth and 6 or more teeth follow a linear path. Compared to no comorbidities, the odds of losing 6 or more teeth increased with 1, 2, or 3+ comorbidities. This study provides significant information about the quantification of comorbidities and its direct correlation with the increased odds of tooth loss. This study also highlighted the protective effect of periodontal treatment on tooth loss. This knowledge can be useful to dental care providers to understand the risk of tooth loss in their patient population.

Mapping the industries’ willingness to pay for unrestricted electricity supply

The supply of electric power plays a crucial role in industrial production, and the current scarcity of electricity prevailing in the industries necessitates willingness of industries to pay higher price for energy supply. This paper explores willingness of the industries to pay for adequate electricity supply and proper management of electricity in 279 industries located in the industrial estates of Kathmandu valley. The required information was drawn from 279 industries through a structured questionnaire based on the interviews. Tobit model and survey results show that information of outage and frequency of outage resulted in positive and statistically significant effects. For the perpetual electricity supply, 94% of the industries are ready to pay higher rate of payment for the use of electricity. The findings infer that Nepal Electricity Authority should improve transparency, connection cost mechanism, regulate the electrical profession and strengthen power factors and operational efficiency to resolve the energy shortage faced by the manufacturing industries of Nepal. Thus, the study concludes that along with the skyrocketing population size, people also require increasing number of commodities and industries are forced for more production to meet these demands. So, adequate supply of electricity in the industrial area plays a complementary role in capital growth and production.

Transaksi Jual Beli Foreign Exchange Secara Online Perspektif Hukum Islam

This article The development of the latest technology cannot be separated from its influence on the lifestyle trends and human economic behavior, as well as investment behavior. Forex online trading includes financial investments, especially in investments in the field of money markets and commodity futures exchanges. The author is of the view that the online forex trading transaction law is haram because it does not fulfill the pillars and conditions of sale and purchase and contains elements of gharar, maisir (gambling), usury and violates the provisions of al-sharf that is the element of speculation / chance, and this investment is classified in trading futures (future market) means the place / facility of buying and selling contracts for a number of commodities or financial instruments at a certain price whose agreed delivery of goods will be carried out in the future.

Extreme downside risk co-movement in commodity markets during distress periods: a multidimensional scaling approach

ABSTRACTWe analyze the co-movement of a number of commodity markets in extreme financial episodes worldwide. More specifically, we provide extreme downside risk co-movement maps of these markets during six recent distress periods. We follow an expected shortfall-multidimensional scaling approach, which allows for an easy classification of markets according to their dynamics in risky episodes. No clear risk co-movement patterns are observed, nor spillover effects are detected. Financialization and speculation might have played some role in the dynamics of price and risk only in food commodity markets during the oil price increase 2007–2008.

Exploring Stakeholder Consensus for Multiple Outcomes in Agriculture: An Iowa Case Study

Extensive row-crop agricultural production systems dominant in the United States Corn Belt are designed to produce high yields of a small number of commodities at low production costs. While remarkably valuable, this model of agriculture is directly and indirectly associated with significant externalized public costs and questions about its long-term viability. Agro-environmental conservation policy in the United States has failed to deliver desired environmental outcomes at broad scales, in part, because policy is supply-oriented with scaled financial and technical incentives aimed at the interests of individual farm managers. Understanding broader stakeholder demand relative to agro-ecosystem outcomes is fundamental to modifying policy toward outcomes. Failed collective policy and management, often indicates failed consensus among stakeholders whose responsibilities are to provide guidance for achieving outcomes. We used a Delphi approach with representatives from Iowa-based agricultural and/or environmental policy, outreach, and industry organizations to explore whether or not consensus may exist regarding desired agricultural outcomes and if so, modes of provision. Through three iterative surveys, we found consensus regarding the array of ecosystem outcomes believed possible within the Iowa agricultural economy. However, when agricultural interests were sorted, a divide emerged between stakeholders who emphasize production agriculture and those who favor a more multi-outcome oriented agriculture that emphasizes multiple ecosystem services. Nevertheless, study participants identified several key ecosystem outcomes, and methods for providing them that are strongly compatible with and support private commodity driven land use while mitigating costly public externalities. A broad and simple six-point framework emerged from our data to contextualize questions and discussions of agricultural land-use management among stakeholders. This framework includes people, their expectations and values, land, management, and ecosystem processes in addition to ecosystem services. Broadening and bounding discourse in these ways may facilitate a shared appreciation of human-nature interconnections and more progressive policy reform that facilitates understanding of land-use decision making within agricultural contexts in ways that benefit all stakeholders.

Optimal sharing with an infinite number of commodities in the presence of optimistic and pessimistic agents

We prove that under mild conditions individually rational Pareto optima will exist even in the presence of non-convex preferences. We consider decision-makers (DMs) dealing with a countable flow of pay-offs or choosing among financial assets whose outcomes depend on the realization of a countable set of states of the world. Our conditions for the existence of Pareto optima can be interpreted as a requirement of impatience in the first context and of some pessimism or not unrealistic optimism in the second context. A non-existence example is provided when, in the second context, some DM is too optimistic. We furthermore show that at an individually rational Pareto optimum at most one strictly optimistic DM will avoid ruin at each state or date. Considering a risky context, this entails that even if risk averters will share risk in a comonotonic way as usual, at most one classical strong risk lover will avoid ruin at each state or date. Finally, some examples illustrate circumstances when a risk averter could take advantage of sharing risk with a risk lover rather than with a risk averter.

Analysis of budget for interdiction on multicommodity network flows

In this paper, we concentrate on computing several critical budgets for interdiction of the multicommodity network flows, and studying the interdiction effects of the changes on budget. More specifically, we first propose general interdiction models of the multicommodity flow problem, with consideration of both node and arc removals and decrease of their capacities. Then, to perform the vulnerability analysis of networks, we define the function F(R) as the minimum amount of unsatisfied demands in the resulted network after worst-case interdiction with budget R. Specifically, we study the properties of function F(R), and find the critical budget values, such as $$R_a$$Ra, the largest value under which all demands can still be satisfied in the resulted network even under the worst-case interdiction, and $$R_b$$Rb, the least value under which the worst-case interdiction can make none of the demands be satisfied. We prove that the critical budget $$R_b$$Rb for completely destroying the network is not related to arc or node capacities, and supply or demand amounts, but it is related to the network topology, the sets of source and destination nodes, and interdiction costs on each node and arc. We also observe that the critical budget $$R_a$$Ra is related to all of these parameters of the network. Additionally, we present formulations to estimate both $$R_a$$Ra and $$R_b$$Rb. For the effects of budget increasing, we present the conditions under which there would be extra capabilities to interdict more arcs or nodes with increased budget, and also under which the increased budget has no effects for the interdictor. To verify these results and conclusions, numerical experiments on 12 networks with different numbers of commodities are performed.

THE ROLE OF FORWARD MARKETS COMMISSION IN INDIAN COMMODITY MARKETS

This paper examines the role of Forward Markets Commission (FMC) in Indian Commodity Markets. The Results show important developments of Forward Markets Commission. Commodity futures and derivatives have a crucial role to play in the price risk management process, especially in agriculture sector. The significance of commodity derivatives has increased in the current scenario. India has long history of trade in commodity derivatives. Organized commodity derivatives in India started as early as 1875, barely about a decade after they started in Chicago. Since 2003, when commodity futures’ trading was permitted, commodity futures market in India has experienced an unprecedented boom in terms of the number of modern exchanges, number of commodities allowed for derivatives trading as well as the value of futures trading in commodities. There are 6 national and 16 regional commodity exchanges recognized and regulated by the FMC. Different types of commodities such as agricultural; bullion, plantation, energy etc. is traded on commodity exchanges in the country. So considering these points an attempt has been made to know the regulatory framework of commodity futures and derivatives market in India and various developments in Indian commodity market and commodity exchanges. This study is an attempt to investigate the performance of Forward Markets Commission in India and its role in Indian commodity market.

On the value of small‐scale GE models

AbstractThe field of international economics has made frequent use of general equilibrium models in order to investigate the nature of those possible comparative static equilibrium solutions that seem somewhat paradoxical. Frequently the analysis is done for settings in which the number of commodities, countries, and/or factors of production is assumed to be rather small. For example, the classic Ricardian model making use of the concept of comparative advantage based on comparisons of efficient ratios of country productivities has solutions that hold for any number of countries or commodities. A number of different issues, such as stability conditions and the transfer problem, are discussed in which surprising equilibrium outcomes possible in a general situation can be understood more easily in a small‐scale setting.

A bi-objective column generation algorithm for the multi-commodity minimum cost flow problem

We present a column generation algorithm for solving the bi-objective multi-commodity minimum cost flow problem. This method is based on the bi-objective simplex method and Dantzig–Wolfe decomposition. The method is initialised by optimising the problem with respect to the first objective, a single objective multi-commodity flow problem, which is solved using Dantzig–Wolfe decomposition. Then, similar to the bi-objective simplex method, our algorithm iteratively moves from one non-dominated extreme point to the next one by finding entering variables with the maximum ratio of improvement of the second objective over deterioration of the first objective. Our method reformulates the problem into a bi-objective master problem over a set of capacity constraints and several single objective linear fractional sub-problems each over a set of network flow conservation constraints. The master problem iteratively updates cost coefficients for the fractional sub-problems. Based on these cost coefficients an optimal solution of each sub-problem is obtained. The solution with the best ratio objective value out of all sub-problems represents the entering variable for the master basis. The algorithm terminates when there is no entering variable which can improve the second objective by deteriorating the first objective. This implies that all non-dominated extreme points of the original problem are obtained. We report on the performance of the algorithm on several directed bi-objective network instances with different characteristics and different numbers of commodities.

Causes of waste across multi-tier supply networks: Cases in the UK food sector

This research has investigated UK food supply networks to identify the dominant causes of food waste. The aim was to develop our understanding of environmental management across multi-tier networks, with specific reference to food waste. The supply networks of 15 food commodities were investigated following a multiple case study design. A total of 101 semi-structured interviews were conducted including retailers (11), wholesalers (2), fruit and vegetable suppliers (41), and cutting plants/abattoirs (47). Waste arising across each of the 15 networks was quantified and the dominant causes of waste were identified, leading to a series of propositions to explain the management practices that trigger waste in food networks. These propositions relate to transparency of demand information, quality management, process controls, shelf-life management and packaging design, and provide insights into the actions required to mitigate the environmental impact of food production. Although the research was restricted to 15 food commodities in the UK, the findings and methods can help to motivate further research in other countries and sectors. The research is unique in terms of the scale of the data collection effort (number of commodities and interviews) and in its scope (multi-tier networks). Given the social, economic and environmental implications of food production and consumption the findings are relevant to a wide range of stakeholders in the sector.

Delay and probability discounting of multiple commodities in smokers and never-smokers using multiple-choice tasks

The purpose of the present study was to investigate temporal and probabilistic discounting in smokers and never-smokers, across a number of commodities, using a multiple-choice method. One hundred and eighty-two undergraduate university students, of whom 90 had never smoked, 73 were self-reported light smokers (<10 cigarettes/day), and 17 were heavy smokers (10+cigarettes/day), completed computerized batteries of delay and probability discounting questions pertaining to a total of eight commodities and administered in a multiple-choice format. In addition to cigarettes, monetary rewards, and health outcomes, the tasks included novel commodities such as ideal dating partner and retirement income. The results showed that heavy smokers probability discounted commodities at a significantly shallower rate than never-smokers, suggesting greater risk-taking. No effect of smoking status was observed for delay discounting questions. The only commodity that was probability discounted significantly less than others was 'finding an ideal dating partner'. The results suggest that probability discounting tasks using the multiple-choice format can discriminate between non-abstaining smokers and never-smokers and could be further explored in the context of behavioral and drug addictions.

Effect of Age, Body Weight and Multiple Mating on Copitarsia decolora (Lepidoptera: Noctuidae) Reproductive Potential and Longevity

Successful behavioral-based control methods rely on the accurate knowledge of the mating dynamics of the target insect. Age at first mating affects reproductive potential and the chance of multiple mating. The cabbage moth, Copitarsia decolora (Guenee) is an important pest of a number of commodities. We investigated combinations of age, body size and mating history to determine how these variables affect insect reproductive capacity. Fecundity and fertility decreased as the age of mating pairs increased, heavy and average sized females laid more eggs than light females. Female multiple mating did not enhance fecundity nor fertility potential. Furthermore, spermatophore size did not determine female re-mating behavior. However, female fecundity and fertility was related to the male mating history. Our results show that SIT is a valuable tool for controlling this pest.

Towards Duality of Multicommodity Multiroute Cuts and Flows: Multilevel Ball-Growing

An elementary h-route flow, for an integer h≥1, is a set of h edge-disjoint paths between a source and a sink, each path carrying a unit of flow, and an h-route flow is a non-negative linear combination of elementary h-route flows. An h-route cut is a set of edges whose removal decreases the maximum h-route flow between a given source-sink pair (or between every source-sink pair in the multicommodity setting) to zero. The main result of this paper is an approximate duality theorem for multicommodity h-route cuts and flows, for h≤3: The size of a minimum h-route cut is at least f/h and at most O(log4 k⋅f) where f is the size of the maximum h-route flow and k is the number of commodities. The main step towards the proof of this duality is the design and analysis of a polynomial-time approximation algorithm for the minimum h-route cut problem for h=3 that has an approximation ratio of O(log4 k). Previously, polylogarithmic approximation was known only for h-route cuts for h≤2. A key ingredient of our algorithm is a novel rounding technique that we call multilevel ball-growing. Though the proof of the duality relies on this algorithm, it is not a straightforward corollary of it as in the case of classical multicommodity flows and cuts. Similar results are shown also for the sparsest multiroute cut problem.