# Peter KlingUniversity of Hamburg | UHH · Department of Informatics

Peter Kling

Prof. Dr.

## About

55

Publications

1,636

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406

Citations

Citations since 2016

Introduction

Additional affiliations

September 2016 - present

January 2015 - September 2016

June 2014 - January 2015

## Publications

Publications (55)

We consider a swarm of $n$ robots in a $d$-dimensional Euclidean space. The robots are oblivious (no persistent memory), disoriented (no common coordinate system/compass), and have limited visibility (observe other robots up to a constant distance). The basic formation task gathering requires that all robots reach the same, not predefined position....

We present a dataset containing source code solutions to algorithmic programming exercises solved by hundreds of Bachelor-level students at the Universität Hamburg. These solutions were collected during the winter semesters 2019/2020, 2020/2021 and 2021/2022. The dataset contains a set of solutions to a total of 21 tasks written in Java as well as...

Most existing robot formation problems seek a target formation of a certain minimal and, thus, efficient structure. Examples include the Gathering and the Chain-Formation problem. In this work, we study formation problems that try to reach a maximal structure, supporting, for example, an efficient coverage in exploration scenarios. As a first step...

We consider minimum-cardinality Manhattan connected sets with arbitrary demands: Given a collection of points P in the plane, together with a subset of pairs of points in P (which we call demands), find a minimum-cardinality superset of P such that every demand pair is connected by a path whose length is the \(\ell _1\)-distance of the pair. This p...

Population protocols are a model for distributed computing that is focused on simplicity and robustness. A system of n identical agents (finite state machines) performs a global task like electing a unique leader or determining the majority opinion when each agent has one of two opinions. Agents communicate in pairwise interactions with randomly as...

We consider the plurality consensus problem among $n$ agents. Initially, each agent has one of $k$ different opinions. Agents choose random interaction partners and revise their state according to a fixed transition function, depending on their own state and the state of the interaction partners. The goal is to reach a consensus configuration in wh...

Consider a set P of points in the unit square U, one of them being the origin. For each point p in P you may draw a rectangle in U with its lower-left corner in p. What is the maximum area such rectangles can cover without overlapping each other? Freedman [1969] posed this problem in 1969, asking whether one can always cover at least 50% of U. Over...

We consider a scheduling problem with resource-dependent processing speeds in which n jobs have to be scheduled on m machines that share a common resource. The resource may be distributed arbitrarily among the machines. This distribution is under the control of the scheduler and can be changed over time. Each job j has a processing volume \(p_j \in...

Most existing robot formation problems seek a target formation of a certain minimal and, thus, efficient structure. Examples include the Gathering and the Chain-Formation problem. In this work, we study formation problems that try to reach a maximal structure, supporting for example an efficient coverage in exploration scenarios. A recent example i...

We consider minimum-cardinality Manhattan connected sets with arbitrary demands: Given a collection of points $P$ in the plane, together with a subset of pairs of points in $P$ (which we call demands), find a minimum-cardinality superset of $P$ such that every demand pair is connected by a path whose length is the $\ell_1$-distance of the pair. Thi...

Most existing robot formation problems seek a target formation of a certain \emph{minimal} and, thus, efficient structure. Examples include the Gathering and the Chain-Formation problem. In this work, we study formation problems that try to reach a \emph{maximal} structure, supporting for example an efficient coverage in exploration scenarios. A re...

Organization and government networks are a target of Advanced Persistent Threats (APTs), i.e., stealthy attackers that infiltrate networks slowly and usually stay undetected for long periods of time. After an attack has been discovered, security administrators have to manually determine which hosts were compromised to clean and restore them. For th...

We consider simple models of swarms of identical, anonymous robots: they are points in the plane and “see” only their neighbors (robots within distance one). We will deal with distributed local protocols of such swarms that result in formations like “gathering at one point”. The focus will be on protocols assuming a continuous time model. We presen...

We consider the following load balancing process for $m$ tokens distributed arbitrarily among $n$ nodes connected by a complete graph: In each time step a pair of nodes is selected uniformly at random. Let $\ell_1$ and $\ell_2$ be their respective number of tokens. The two nodes exchange tokens such that they have $\lceil(\ell_1 + \ell_2)/2\rceil$...

A population protocol can be viewed as a sequence of pairwise interactions of $n$ agents (nodes). During one interaction, two agents selected uniformly at random update their states by applying a specified deterministic transition function. In a long run, the whole system should stabilize at the correct output property. The main performance objecti...

Population protocols are a distributed model focused on simplicity and robustness. A system of $n$ identical nodes must perform a global task like electing a unique leader or determining the majority opinion when each node has one of two opinions. Nodes communicate in pairwise interactions. Communication partners cannot be chosen but are assigned r...

A fundamental problem in distributed computing is the distribution of requests to a set of uniform servers without a centralized controller. Classically, such problems are modeled as static balls into bins processes, where m balls (tasks) are to be distributed among n bins (servers). In a seminal work, Azar et al. (SIAM J Comput 29(1):180–200, 1999...

We consider the problem of scheduling a number of jobs on m identical processors sharing a continuously divisible resource. Each job j comes with a resource requirement Open image in new window. The job can be processed at full speed if granted its full resource requirement. If receiving only an x-portion of \(r_j\), it is processed at an x-fractio...

We study consensus processes on the complete graph of n nodes. Initially, each node supports one up to n different opinions. Nodes randomly and in parallel sample the opinions of constantly many nodes. Based on these samples, they use an update rule to change their own opinion. The goal is to reach consensus, a configuration where all nodes support...

We consider a scheduling problem on m identical processors sharing an arbitrarily divisible resource. In addition to assigning jobs to processors, the scheduler must distribute the resource among the processors (e.g., for three processors in shares of 20%, 15%, and 65%) and adjust this distribution over time. Each job j comes with a size pj ∈ R and...

We consider the following balls-into-bins process with $n$ bins and $m$ balls: each ball is equipped with a mutually independent exponential clock of rate 1. Whenever a ball's clock rings, the ball samples a random bin and moves there if the number of balls in the sampled bin is smaller than in its current bin. This simple process models a typical...

We consider an extension of the dynamic speed scaling scheduling model introduced by Yao et al. [1]: A set of jobs, each with a release time, deadline, and workload, has to be scheduled on a single, speed-scalable processor. Both the maximum allowed speed of the processor and the energy costs may vary continuously over time. The objective is to fin...

We study consensus processes on the complete graph of $n$ nodes. Initially, each node supports one from up to n opinions. Nodes randomly and in parallel sample the opinions of constant many nodes. Based on these samples, they use an update rule to change their own opinion. The goal is to reach consensus, a configuration where all nodes support the...

We consider the setting of a sensor that consists of a speed-scalable processor, a battery, and a solar cell that harvests energy from its environment at a time-invariant recharge rate. The processor must process a collection of jobs of various sizes. Jobs arrive at different times and have different deadlines. The objective is to minimize the *rec...

We give a polynomial time algorithm to compute an optimal energy and fractional weighted flow trade-off schedule for a speed-scalable processor with discrete speeds. Our algorithm uses a geometric approach that is based on structural properties obtained from a primal–dual formulation of the problem.

A fundamental problem in distributed computing is the distribution of requests to a set of uniform servers without a centralized controller. Classically, such problems are modelled as static balls into bins processes, where m balls (tasks) are to be distributed to n bins (servers). In a seminal work, [Azar et al.; JoC'99] proposed the sequential st...

A fundamental problem in distributed computing is the distribution of requests to a set of uniform servers without a centralized controller. Classically, such problems are modeled as static balls into bins processes, where $m$ balls (tasks) are to be distributed to $n$ bins (servers). In a seminal work, Azar et al. proposed the sequential strategy...

We consider \emph{plurality consensus} in a network of $n$ nodes. Initially, each node has one of $k$ opinions. The nodes execute a (randomized) distributed protocol to agree on the plurality opinion (the opinion initially supported by the most nodes). Nodes in such networks are often quite cheap and simple, and hence one seeks protocols that are n...

The most commonly studied energy management technique is speed scaling, which involves operating the processor in a slow, energy-efficient mode at non-critical times, and in a fast, energy-inefficient mode at critical times. The natural resulting optimization problems involve scheduling jobs on a speed-scalable processor and have conflicting dual o...

We consider online optimization problems in which certain goods have to be acquired in order to provide a service or infrastructure. Classically, decisions for such problems are considered as final: one buys the goods. However, in many real world applications, there is a shift away from the idea of buying goods. Instead, leasing is often a more fle...

We study a scenario in which n mobile robots with a limited viewing range are distributed in the Euclidean plane and have to solve a formation problem. The formation problems we consider are the Gathering problem and the Chain-Formation problem. In the Gathering problem, the robots have to gather in one (not predefined) point, while in the Chain-Fo...

In this paper we introduce 'On-The-Fly Computing', our vision of future IT services that will be provided by assembling modular software components available on world-wide markets. After suitable components have been found, they are automatically integrated, configured and brought to execution in an On-The-Fly Compute Center. We envision that these...

We consider the problem of scheduling a number of jobs on m identical processors sharing a continuously divisible resource. Each job j comes with a resource requirement rj∈[0,1]. The job can be processed at full speed if granted its full resource requirement. If receiving only an x-portion of r_j, it is processed at an x-fraction of the full speed....

We give a polynomial time algorithm to compute an optimal energy and fractional weighted flow trade-off schedule for a speed-scalable processor with discrete speeds. Our algorithm uses a geometric approach that is based on structural properties obtained from a primal-dual formulation of the problem. © Antonios Antoniadis, Neal Barcelo, Mario Consue...

We present a new online algorithm for profit-oriented scheduling on multiple speed-scalable processors and provide a tight analysis of the algorithm’s competitiveness. Our results generalize and improve upon work by Chan et al. [2010], which considers a single speed-scalable processor. Using significantly different techniques, we can not only exten...

We present and study a new model for energy-aware and profit-oriented scheduling on a single processor. The processor features dynamic speed scaling as well as suspension to a sleep mode. Jobs arrive over time, are preemptable, and have different sizes, values, and deadlines. On the arrival of a new job, the scheduler may either accept or reject th...

Network creation games model the creation and usage costs of networks formed by a set of selfish peers. Each peer has the ability to change the network in a limited way, e.g., by creating or deleting incident links. In doing so, a peer can reduce its individual communication cost. Typically, these costs are modeled by the maximum or average distanc...

We consider an online facility location problem where clients arrive over time and their demands have to be served by opening facilities and assigning the clients to opened facilities. When opening a facility we must choose one of K different lease types to use. A lease type k has a certain lease length l
k
. Opening a facility i using lease type k...

We consider a scenario in which n mobile robots with a limited viewing range are distributed arbitrarily in the plane, such that the visibility graph of the robots is connected. The goal is to gather the robots in one (not predefined) point. Each robot may base its decision where to move only on the current relative positions of the robots which ar...

Web Computing is a variant of parallel computing where the idle times of PCs donated by worldwide distributed users are employed to execute parallel programs. The PUB-Web library developed by us supports this kind of usage of computing resources. A major problem for the efficient execution of such parallel programs is load balancing. In the Web Com...

Given a set of n mobile robots in the d-dimensional Euclidean space, the goal is to let them converge to a single not predefined point. The challenge is that the
robots are limited in their capabilities. Robots can, upon activation, compute the positions of all other robots using an
individual affine coordinate system. The robots are indistinguisha...

We present a randomized distributed approximation algorithm for the metric
uncapacitated facility location problem. The algorithm is executed on a
bipartite graph in the Congest model yielding a (1.861 + epsilon) approximation
factor, where epsilon is an arbitrary small positive constant. It needs
O(n^{3/4}log_{1+epsilon}^2(n) communication rounds...

Gathering n mobile robots in one single point in the Euclidean plane is a widely studied problem from the area of robot formation problems.
Classically, the robots are assumed to have no physical extent, and they are able to share a position with other robots. We
drop these assumptions and investigate a similar problem for robots with (a spherical)...

Consider two far apart base stations connected by an arbitrarily winding chain of n relay robots to transfer messages between them. Each relay acts autonomously, has a limited communication range, and knows only a small, local part of its environment. We seek a strategy for the relays to minimize the chain's length. We describe a large strategy cla...

We are given an arbitrarily shaped chain of n robots with fixed end points in the plane. We assume that each robot can only see its two neighbors in the chain, which have
to be within its viewing range. The goal is to move the robots to the straight line between the end points. Each robot has
to base the decision where to move on the relative posit...