Contraction Problem Research Articles

An Option-Revenue Sharing Coordination Contract with Price and Sales Effort Dependent Demand

This study proposes a novel option-revenue sharing coordination contract framework. In the proposed model, the retailer determines the number of order sales effort. The manufacturer sets the price of products for the wholesale strategy. The investigated supply chain problem analyzes the results of different strategies. In the proposed coordination contract problem, two types of games including retailer-based game and manufacturer-based Stackelberg game are considered. In both cases the retailer adopts the value of order and the sales effort and the manufacturer determines the wholesale price. To assess the performance of the proposed contract, a wholesale and a basic selection contract are considered in the model. To obtain the Nash equilibrium in the retailer-based state of the proposed option-revenue sharing coordination contract problem, a hybrid algorithm consisting of a heuristic and a genetic algorithm is proposed by considering the computational complexities of the proposed model. A numerical comparison between the proposed contract and other cases demonstrates that the option-revenue sharing contract significantly dominates the basic option and the wholesale price contract. Finally, we implemented some numerical experiments on the critical parameters of the contract. Based on the results, increasing the price-dependency of demand results in less number of products ordered by the retailer.

Curbing Illegal Grazing Through Mediating Interests of Local Communities in East Nusa Tenggara Province, Indonesia

Communities living surrounding forest have used state forest for grazing area in East Nusa Tenggara Timur Province, Indonesia for a long time.  However, Indonesia government have not given them a permit for managing state forest. Government will involve communities in state forest management   to generate people income but government ,as a principal, was worried that the communities, as agent,  will act in the way contrary to the interest of government. We used a principal agent theory to analyze principal agent problems which will occur if communities manage state forest for silvopasture purpose. The research showed that there are some principal agent problems in silvopasture contract if government give communities a permit for silvopasture purpose, i.e. communities, as agent, are not willing to plant trees and keep forest. Government must control communities to prevent some principal-agent problems in silvopasture contract.

New sufficient criteria for epsilon-contraction of a class of nonlinear diference system with continuous time

Contraction property of dynamical systems, especially difference systems, is one of the qualitative properties which have attracted much attention from many researchers for recent decades. Contraction of dynamical systems has many practical applications which means that two trajectories of the system convergence to each other when the time reaches to positive infinity. In this paper, by improving some existing approaches, we present a new approach to contraction problem of a class of nonlinear time-varying delay difference system with continuous time. We generalize the definition of contraction to -contraction. Then, we give some new explicit sufficient criteria for -contraction and global exponential stability of the mentioned system. Furthermore, we investigate-contraction of perturbed difference systems with continuous time under nonlinear perturbations in which perturbations are general time-varying functions. Then we obtain a new explicit-contraction bound for such systems subject to nonlinear time-varying perturbations. The obtained theorems generalize some existing results in the literature as particular cases. An example is given to illustrate the obtained results.

Delay-variation constrained spectrum extraction and contraction problem for multipath routing on elastic optical networks

Delay-variation constrained spectrum extraction and contraction problem for multipath routing on elastic optical networks

Research on Accounting Recognition and Measurement Related to Energy Management Contract

The energy crisis of the 1970s prompted Western developed countries to explore ways to save energy by improving energy efficiency. The United States is the first to propose an energy management contract model that relies on market mechanisms to promote energy conservation. Its development has obvious bottom-up, market-driven economic characteristics. In the 1990s, the energy management contract mechanism was introduced into China, and its development has obvious top-down, policy-driven economic characteristics. Energy management contract is a relatively new business model. With the advancement of society, the form of energy management contract has gradually increased. At present, the accounting system for this type of business model has not been formed. Based on this situation, there are more and more problems in energy management contract. So far, China still lacks a unified accounting business accounting standard, and there have been many disputes in accounting practice. This has greatly affected the promotion and implementation of the new mechanism of domestic energy management contract, which inevitably has a certain impact on the development of the contract energy industry.

Negotiating a Better Future: How Interpersonal Skills Facilitate Intergenerational Investment*

AbstractUsing a randomized controlled trial, we study whether a negotiation skills training can improve girls’ educational outcomes in a low-resource environment. We find that a negotiation training given to eighth-grade Zambian girls significantly improved educational outcomes over the next three years, and these effects did not fade out. To better understand mechanisms, we estimate the effects of two alternative treatments. Negotiation had much stronger effects than an informational treatment, which had no effect. A treatment designed to have more traditional girls’ empowerment effects had directionally positive but insignificant educational effects. Relative to this treatment, negotiation increased enrollment in higher-quality schooling and had larger effects for high-ability girls. These findings are consistent with a model in which negotiation allows girls to resolve incomplete contracting problems with their parents, yielding increased educational investment for those who experience sufficiently high returns. We provide evidence for this channel through a lab-in-the-field game and follow-up survey with girls and their guardians.

Path Contraction Faster than $2^n$

A graph $G$ is contractible to a graph $H$ if there is a set $X \subseteq E(G)$, such that $G/X$ is isomorphic to $H$. Here, $G/X$ is the graph obtained from $G$ by contracting all the edges in $X$. For a family of graphs $\cal F$, the $\mathcal{F}$-Contraction problem takes as input a graph $G$ on $n$ vertices, and the objective is to output the largest integer $t$, such that $G$ is contractible to a graph $H \in {\cal F}$, where $|V(H)|=t$. When $\cal F$ is the family of paths, then the corresponding $\mathcal{F}$-Contraction problem is called Path Contraction. The problem Path Contraction admits a simple algorithm running in time $2^{n}\cdot n^{{\mathcal{O}}(1)}$. In spite of the deceptive simplicity of the problem, beating the $2^{n}\cdot n^{{\mathcal{O}}(1)}$ bound for Path Contraction seems quite challenging. In this paper, we design an exact exponential time algorithm for Path Contraction that runs in time ${{1.99987}^n}\cdot n^{{\mathcal O}(1)}$. We also define a problem called 3-Disjoint Connected Subgraphs and design an algorithm for it that runs in time $1.88^n\cdot n^{{\mathcal O}(1)}$. The above algorithm is used as a subroutine in our algorithm for Path Contraction.

From Late Medieval City Employees to Early Modern Civil Servants. Employment Relationships as Reflected in the Frankfurt Contract Documents

Using the example of Frankfurt am Main, this article traces the development of the employment relationships of municipal employees between the last quarter of the 14th century and the early 19th century, on the basis of the collection of their contracts, the so-called service letters. The contents of this collection determine the study’s chronological range. All sectors of the municipal service are covered. The study also highlights the limitations of the source material regarding the employment of women and socially marginalised groups.Key aspects studied are fundamental contractual problems such as contract duration and termination, salary, risk distribution and disciplinary measures. Particular attention is paid to the resolution of conflicts between the city and its employees, including the problems of limitations on legal recourse, the settlement of conflicts before the highest courts of the Empire, and the methods and motives of consensual dispute resolution. The study also considers how the findings from Frankfurt relate to the situation in other cities of the Holy Roman Empire. Furthermore, it focuses on the historical context of the changes in contractual practices and clauses. Important events in the city’s political and constitutional history, such as the attainment of the status of imperial city, the Reformation, and the 17th- and 18th-century conflicts between the city authorities and its citizens, had considerable influence on Frankfurt’s administration and municipal service system.Finally, the findings will be integrated into a number of early modern research narratives, such as the concept of gute Policey, social disciplining, and professionalisation, as well as more recent research questions of exchange fairness and of asymmetric dependence. The various analytical approaches together reveal a co-evolution of municipal administration and employment relationships that led to the emergence of a municipal civil service. Zitiervorschlag: Pierson, Thomas, From Late Medieval City Employees to Early Modern Civil Servants. Employment Relationships as Reflected in the Frankfurt Contract Documents, in: Rechtsgeschichte - Legal History Rg 28 (2020) 68-93, online: http://dx.doi.org/10.12946/rg28/068-093

Problem of Agency in Mudarabah Contract

This study evaluated agency problem in mudarabah (profit sharing) contract and suggests some prudent and comprehensive mechanisms to mitigate this problem from Islamic perspectives. Agency problem in mudarabah contract can cause a number of difficulties if there is no effective information transfer between the contracting parties. Full disclosure of information from the entrepreneur (agent or mudarib) that manages the fund on behalf of a capital provider (principal or rabbulmaal) can help to reduce misinformation and assist decision making. Some approaches that can be taken to avoid asymmetric information are compatible incentive contract, screening and monitoring process, shuratic (social learning) process and execution of Islamic code of conduct. This study highlights the roles of the Islamic code of conduct and shuratic process in mitigating agency problems in mudarabah contract.

Problems of Social Contracts with Dysfunctional Families

Problems of Social Contracts with Dysfunctional Families

Dynamics of active swelling in contractile polymer gels

The transient behaviour of extremely soft and soft active polymer gels is investigated through a stress-diffusion model which takes into account the active behaviour of the polymer network when molecular motors are included in the solvent bath. The latter is described as a remodeling of the polymer network. The problem of isotropic contraction induced by a homogeneous distribution of molecular motors is explicitly set up and solved. The results have been compared with experiments and show excellent agreement.

Needles and straw in a haystack: Robust confidence for possibly sparse sequences

In the general signal$+$noise (allowing non-normal, non-independent observations) model, we construct an empirical Bayes posterior which we then use for uncertainty quantification for the unknown, possibly sparse, signal. We introduce a novel excessive bias restriction (EBR) condition, which gives rise to a new slicing of the entire space that is suitable for uncertainty quantification. Under EBR and some mild exchangeable exponential moment condition on the noise, we establish the local (oracle) optimality of the proposed confidence ball. Without EBR, we propose another confidence ball of full coverage, but its radius contains an additional $\sigma n^{1/4}$-term. In passing, we also get the local optimal results for estimation, posterior contraction problems, and the problem of weak recovery of sparsity structure. Adaptive minimax results (also for the estimation and posterior contraction problems) over various sparsity classes follow from our local results.

The Matzak judgment of the CJEU: The concept of worker and the blurring frontiers of work and rest time

The CJEU’S Matzak judgment raises diverse and important questions concerning (not only) working time regulation in the European Union. The present special issue sheds light on some of these questions, more specifically with regard to the Working Time Directive‘s personal scope as well as the notions of working time and rest time under EU law. The Directive’s scope is linked to the concept of worker and the criteria to construct it and, in the context of the Matzak case, leads to interesting questions about the position of volunteers in EU law and the problem of concurrent contracts. In this respect, exploring a purposive approach attending to the health and safety aims of the Directive may be fruitful. The boundaries between working time and rest time are far from clear, especially in situations of stand-by and on call time. Here the proposal of an intermediate category related to the idea of quality of rest time is discussed.

Spectrum Expansion/Contraction and Survivable Routing and Spectrum Assignment problems on EONs with time-varying traffic

For serving time-varying traffic on an Elastic Optical Networks (EONs), the spectrum allocated previously for the connection request should be expanded or contracted to meet the traffic requirement. For the survivable connection, both the primary and the backup lightpaths of the connection request should be expanded/contracted at the same time. In this paper, the Survivable Routing and Spectrum Allocation (SRSA) problem and the Spectrum Expansion Contraction (SEC) problem for SRSA on EONs with time-varying traffic are studied. In this article, two protecting schemes, Dedicated Path Protection (DPP) and Shared Backup Path Protection (SBPP) are considered. For each protecting scheme, two dynamic survivable routing algorithms and the respective SEC operations are developed to solve it. In the proposed algorithms, both the weighted hop distance and spectrum fragmentation are considered jointly. These algorithms are examined through simulations to find the best parameter for each algorithm. The results show that the blocked ratio (BR) of requests can be reduced by about 3%, if the spectrum fragmentation is considered. And, using SEC operation in time-varying traffic can reduce the BR of request about 1% and speed up the computation compared to the normal release and add operation.

Optimal agency contract for incentive and control under moral hazard in dynamic electric power networks

The authors propose an optimal contract mechanism under moral hazard in discrete-time dynamic electric power networks. As the utility (system operator) cannot adjust the control input of the agents (end-users) directly in real time out of respect for individual decision–making, the agents’ control input maximising their own profit does not always maximise social welfare. To avoid the issue, the authors introduce an aggregator as intermediary between the utility and the agents. The aggregator pays compensation for defective ancillary services, which are caused by random disturbance and the agents’ voluntary control. To reduce the compensation risk, the authors first present an optimal incentive/control contract problem for the aggregator's compensation. The problem is usually regarded as a principal-agent problem under moral hazard in contract theory. However, it is generally difficult to solve a contract problem with dynamics expressed as discrete-time simultaneous Bellman equations and a hierarchical control structure as a Stackelberg game. The authors next show that the problem can be solved by regarding it as a linear-exponential-quadratic-Gaussian dynamic game and employing a numerical optimisation technique. Due to the ex-ante appropriate payment contract, the agents select control inputs preferable for the aggregator. The effectiveness of the proposed contract mechanism is finally demonstrated through simulation.

Optimal decision for two dimensional maintenance service contract involving three parties

A two-dimensional (i.e. time and use) maintenance service contract involving three parties i.e. manufacturer, agent and consumer are considered in this paper. The contract period by the manufacturer/agent begins since the warranty expires (W) until the lifetime of the equipment expires (L). The use of equipment by consumer is modeled with accelerated failure time (AFT) model. AFT model specifies the limit value of permitted equipment usage (Ul). The contract time is limited to t = L, but equipment usage may exceed Ul. High use of equipment will increase consumer revenue. However, the consumer will incur additional costs paid to the manufacturer/agent if the use of equipment exceeds Ul. Therefore, consumers will seek the optimum value of use (U∗) that maximizes the profits. As with consumer, manufacturer and agent also want to maximize their profits. Decision problems in maintenance service contracts involving the three parties will be resolved consider the interaction of the manufacturer and the agent in carrying out maintenance action. One level optimization used if the manufacturer and agent compete with each other. However, if the manufacturer and agent interact in a cooperation, then optimization of the decision model becomes more difficult and should be done with bilevel optimization.

Outsourcing Public Services: Contractibility, Cost, and Quality

AbstractWe review the literature on public sector outsourcing to explore if the theoretical predictions from the incomplete contracts literature hold up to recent empirical evidence. Guided by theory, we arrange services according to the type and magnitude of their contractibility problems. The empirical studies point at rather favourable outsourcing outcomes, in terms of costs and quality, for services without severe contracting problems. The picture is more mixed for services with tougher contracting problems, with the weight of the evidence in favour of public provision. This difference between services is largely in line with the property-rights framework and theories of incomplete contracts.

An improved linear kernel for the cycle contraction problem

The problem of modifying a given graph to satisfy certain properties has been one of the central topics in parameterized tractability study. In this paper, we investigate the cycle contraction problem, which makes a graph into a cycle by edge contractions. The problem was raised by Belmonte et al. [IPEC 2013] and they obtained a linear kernel with at most 6k+6 vertices for it. We provide an improved kernel with at most 5k+4 vertices for the problem in this paper. Our result showcases how to design kernelization algorithm for one problem by exploiting kernels of another problem.

Mutual dependence or state dominance? Large private suppliers and the British state 2010–15

As public outsourcing has grown, the need to understand government's relations with supply side actors has become more important for public administration scholars. The article analyses the role of a small group of large contractors in the British outsourcing system during Britain's Coalition government. These ‘public service conglomerates’ have thus far received little attention in the public administration literature. The article compares two approaches for understanding the role of these corporations and analyses why the corporations faced sometimes severe disruption during the Coalition period in the form of multiple contract problems, conflict with ministers and financial problems. Over the period, the corporations became the objects of policy debate, and what had appeared to be a stable set of arrangements started to fracture. The case shows the value of analysing the political and organizational foundations of contracting arrangements.

Indifference Pricing of Pure Endowments Via BSDEs under Partial Information

In this paper we investigate the pricing problem of a pure endowment contract when the insurer has a limited information on the mortality intensity of the policyholder. The payoff of this kind of policies depends on the residual life time of the insured as well as the trend of a portfolio traded in the financial market, where investments in a riskless asset, a risky asset and a longevity bond are allowed. We propose a modeling framework that takes into account mutual dependence between the financial and the insurance markets via an observable stochastic process, which affects the risky asset and the mortality index dynamics. Since the market is incomplete due to the presence of basis risk, in alternative to arbitrage pricing we use expected utility maximization under exponential preferences as evaluation approach, which leads to the so-called indifference price. Under partial information this methodology requires filtering techniques that can reduce the original control problem to an equivalent problem in complete information. Using stochastic dynamics techniques, we characterize the indifference price of the insurance derivative via the solutions of suitable backward stochastic differential equations.