The Lazy Bureaucrat Scheduling Problem

We introduce a new class of scheduling problems in which the optimization is performed by the worker (single ``machine'') who performs the tasks. A typical worker's objective is to minimize the amount of work he does (he is ``lazy''), or more generally, to schedule as inefficiently (in some sense) as possible. The worker is subject to the constraint that he must be busy when there is work that he can do; we make this notion precise both in the preemptive and nonpreemptive settings. The resulting class of ``perverse'' scheduling problems, which we denote ``Lazy Bureaucrat Problems,'' gives rise to a rich set of new questions that explore the distinction between maximization and minimization in computing optimal schedules.Comment: 19 pages, 2 figures, Latex. To appear, Information and Computatio

Scheduling Algorithms for Procrastinators

This paper presents scheduling algorithms for procrastinators, where the speed that a procrastinator executes a job increases as the due date approaches. We give optimal off-line scheduling policies for linearly increasing speed functions. We then explain the computational/numerical issues involved in implementing this policy. We next explore the online setting, showing that there exist adversaries that force any online scheduling policy to miss due dates. This impossibility result motivates the problem of minimizing the maximum interval stretch of any job; the interval stretch of a job is the job's flow time divided by the job's due date minus release time. We show that several common scheduling strategies, including the "hit-the-highest-nail" strategy beloved by procrastinators, have arbitrarily large maximum interval stretch. Then we give the "thrashing" scheduling policy and show that it is a \Theta(1) approximation algorithm for the maximum interval stretch.Comment: 12 pages, 3 figure

Subset sum problems with digraph constraints

We introduce and study optimization problems which are related to the well-known Subset Sum problem. In each new problem, a node-weighted digraph is given and one has to select a subset of vertices whose total weight does not exceed a given budget. Some additional constraints called digraph constraints and maximality need to be satisfied. The digraph constraint imposes that a node must belong to the solution if at least one of its predecessors is in the solution. An alternative of this constraint says that a node must belong to the solution if all its predecessors are in the solution. The maximality constraint ensures that no superset of a feasible solution is also feasible. The combination of these constraints provides four problems. We study their complexity and present some approximation results according to the type of input digraph, such as directed acyclic graphs and oriented trees

(In)approximability of Maximum Minimal FVS

We study the approximability of the NP-complete \textsc{Maximum Minimal Feedback Vertex Set} problem. Informally, this natural problem seems to lie in an intermediate space between two more well-studied problems of this type: \textsc{Maximum Minimal Vertex Cover}, for which the best achievable approximation ratio is $\sqrt{n}$, and \textsc{Upper Dominating Set}, which does not admit any $n^{1-\epsilon}$ approximation. We confirm and quantify this intuition by showing the first non-trivial polynomial time approximation for \textsc{Max Min FVS} with a ratio of $O(n^{2/3})$, as well as a matching hardness of approximation bound of $n^{2/3-\epsilon}$, improving the previous known hardness of $n^{1/2-\epsilon}$. The approximation algorithm also gives a cubic kernel when parameterized by the solution size. Along the way, we also obtain an $O(\Delta)$-approximation and show that this is asymptotically best possible, and we improve the bound for which the problem is NP-hard from $\Delta\ge 9$ to $\Delta\ge 6$. Having settled the problem's approximability in polynomial time, we move to the context of super-polynomial time. We devise a generalization of our approximation algorithm which, for any desired approximation ratio $r$, produces an $r$-approximate solution in time $n^{O(n/r^{3/2})}$. This time-approximation trade-off is essentially tight: we show that under the ETH, for any ratio $r$ and $\epsilon>0$, no algorithm can $r$-approximate this problem in time $n^{O((n/r^{3/2})^{1-\epsilon})}$, hence we precisely characterize the approximability of the problem for the whole spectrum between polynomial and sub-exponential time, up to an arbitrarily small constant in the second exponent.Comment: 31 pages, 2 figures, ISAAC 2020, Preprint submitted to Journal of Computer and System Science

Designated Hitters, Pinch Hitters, and Bat Boys: Judges Dealing with Judgment and Inexperience, Career Clerks or Term Clerks

Urbanisation is an increasing phenomenon especially the last years, which is of major concern due to the damage that can cause on environmental components such as climate, biosphere, land and water resources. A prevalent way to control this damage and mitigate the negative impacts of urban areas, lately, is considered the use of international tools like BREEAM Communities. BREEAM Communities is a third party assessment and certification standard that assesses, rates and certifies international processes, addressing environmental, social and economic sustainability objectives that can have an impact on large-scale development projects. A prevailing aspect of an urban development process is the urban design part which demands a lot of effort during the whole process. This study, focuses on how BREEAM Communities incorporates and influences the urban design of a large-scale development. By analysis of case studies regarding development projects in Sweden that either used BREEAM Communities or rejected it, qualitative interviews with relevant actors and quantitative analysis of the tool with charts and diagrams, the benefits and the drawbacks of the tool in relation to urban design are being explored. The main methods used for collecting and analysing the data are a theoretical approach, case studies analysis and interviews. Based on the overall qualitative and quantitative results of this study, the tool proved to be urban design sensitive since it includes a wide range of issues related to urban design and in particular, it has the potential to provide inspiration and support to the urban design team from an early stage throughout the process. Finally, a set of certain guidelines for architects and urban designers were prepared in order to optimise their job by setting priorities and to make their work more time and cost efficient.Urbanisering har ökat kraftigt de senaste åren, vilket gör urbaniseringens negativa effekter på miljömässiga beståndsdelar som klimat, biosfär samt mark- och vattenresurser angelägna att utreda. Ett sätt att kontrollera och motverka de negativa miljöeffekterna från städer har varit genom att använda internationella verktyg som BREEAM Communities. BREEAM Communities är en tredjeparts utvärderings- och certifieringsverktyg vilket utvärderar, klassificerar och certifierar internationella processer genom att värdera miljömässigt, socialt och ekonomiskt hållbara mål vilka kan påverka storskaliga utvecklingsprojekt. En stor beståndsdel i ett stadsutvecklingsprojekt är designdelen, vilken kräver mycket fokus under hela processen. Den här uppsatsen fokuserar på hur BREEAM Communities involverar och influerar stadsutvecklingen i ett storskaligt projekt. Genom att analysera utvecklingsprojekt i Sverige som antingen använde BREEAM Communities eller förkastade detta, genom kvalitativa intervjuer med relevanta aktörer och kvantitativa analyser av verktygen genom tabeller och diagram har fördelar och nackdelar med verktygen i relation till stadsutveckling och design utforskats. En teoretisk ansats har använts som huvudmetod för att samla in relevant data. Baserat på de kvalitativa och kvantitativa resultaten framträdde ett resultat som visar att verktygen var användbara vid stadsutveckling eftersom de inkluderar en lång rad olika frågor och har potential att tillhandahålla inspiration och support för stadsutvecklingsteamet redan från ett tidigt stadie i processen. Dessutom var en del hjälpmedel förberedda för arkitekter och urbana designers för att optimera deras arbete genom att sätta upp en prioriteringslista och genom att göra deras arbete mer tids- och kostnadseffektivt.Research project at the Division of Environmental Strategies Analysis, KT

Priority Rules for Multi‐Task Due‐Date Scheduling under Varying Processing Costs

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/135700/1/poms12606.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/135700/2/poms12606_am.pd

Designated Hitters, Pinch Hitters, and Bat Boys: Judges Dealing with Judgment and Inexperience, Career Clerks or Term Clerks

This paper explores the relationship of the law clerk to the judge and why judges decide to make their term clerks career clerks or switch from career clerks back to term clerks. In exploring this issue, 26 judges were interviewed and provided a broad set of reasons both to have a career clerk or to stick with term clerks. The decision to hire a career clerk rests on serendipitous events while the choice to switch back to term clerks is deliberate. In the game of baseball the manager in the World Series has to change tactics when considering how to use the designated hitter. The district judge hiring law clerks has to consider how that person is to be used, as a designated hitter, a pinch hitter or a bat boy. Experience, wisdom, judgment, maturity, and even humility -- aspirational qualities for judges -- are not often found in new law clerks. Delegating the judge\u27s responsibilities to such a person creates risks for the system

Policy implementation under stress: How the Affordable Care Act’s frontline workers cope with the challenges of public service delivery

Public service delivery in the contemporary American state is becoming increasingly challenging. As the implementation of the Affordable Care Act (ACA) shows, new social policies combine high technological and cognitive demands on citizens and government with budget austerity, decentralization and political polarization. Yet, as we argue in this paper, the ACA also shows how frontline workers cope with these challenges by focusing on improving client experiences and policy outcomes. In particular, we consider how non-governmental social-service professionals, critical to contemporary service delivery, cope with high caseloads, legal rigidity, and a lack of policy knowledge on the part of citizens. Variation in coping techniques is consequential; rationing care to deal with large numbers of high-demand clients may lead to poorer service and citizen dissatisfaction. By contrast, techniques like learning and rule bending may actually improve citizens’ experience of policy. To examine patterns of coping in ACA implementation, we present the results of 21 in-depth interviews with navigators, assisters, and Certified Application Counselors in Wisconsin and Minnesota. Across both states, our respondents coped by engaging in instrumental action (learning & collaboration) and rule bending, rather than rationing care, routinizing their work, or rigidly adhering to rules. While these pro-client techniques are both fiscally and organizationally constrained, our interviews reveal that social-service professionals use them even in especially adverse circumstances