Broadcast Routing with Minimum Wavelength Conversion in WDM Optical Networks

We consider dynamic routing of broadcast connections in WDM optical networks. Given the current network state, we want to find a minimum set of network nodes S such that a broadcast routing using only the nodes in S as wavelength conversion nodes can be found. This ensures that the average conversion delay from the source to all destinations is minimized. We refer to the problem as Broadcast Conversion Node Selection (BCNS) problem. We prove that BCNS has no polynomial-time approximation with performance ratio ln n for < 1 unless NPDTIME(n^{O(log log n)}) where n is the number of vertices in the input graph. We present a greedy approximation algorithm for BCNS that achieves approximation ratio 2+ln n. Simulation results show that the algorithm performs very well in practice, obtaining optimal solutions in most of the cases.     

A Tighter Extra-Resource Analysis of Online Deadline Scheduling

This paper is concerned with online algorithms for scheduling jobs with deadlines on a single processor. It has been known for long that unless the system is underloaded, no online scheduling algorithm can be 1-competitive, i.e., matching the performance of the optimal offline algorithm. Nevertheless, recent work has revealed that some online algorithms using a moderately faster processor (or extra processors) can guarantee very competitive performance Kalyanasundaram and Pruhs, 2000 or even be 1-competitive Koo et al., 2002; Lam and To, 2001. This paper takes a further step to investigate online scheduling algorithms with an even higher performance guarantee (i.e., better than 1-competitive algorithms) and in particular, presents an extra-resource analysis of the earliest-deadline-first strategy (EDF) with respect to such a higher performance guarantee.A preliminary version of this paper has been accepted by The Australian Theory Symposium on Computing, 2004.This research was supported in part by Hong Kong RGC Grant HKU-7024/01E.     

Feature Selection for Consistent Biclustering via Fractional 0–1 Programming

Biclustering consists in simultaneous partitioning of the set of samples and the set of their attributes (features) into subsets (classes). Samples and features classified together are supposed to have a high relevance to each other which can be observed by intensity of their expressions. We define the notion of consistency for biclustering using interrelation between centroids of sample and feature classes. We prove that consistent biclustering implies separability of the classes by convex cones. While previous works on biclustering concentrated on unsupervised learning and did not consider employing a training set, whose classification is given, we propose a model for supervised biclustering, whose consistency is achieved by feature selection. The developed model involves solution of a fractional 0–1 programming problem. Preliminary computational results on microarray data mining problems are reported.This research work was partially supported by NSF, NIH and AirForce grants.     

The Center Location Improvement Problem Under the Hamming Distance

In this paper, we consider the center location improvement problems under the sum-type and bottleneck-type Hamming distance. For the sum-type problem, we show that achieving an algorithm with a worst-case ratio of O(log |V|) is NP-hard, and for the bottleneck-type problem, we present a strongly polynomial algorithm.     

Clustering of Microarray data via Clique Partitioning

Microarrays are repositories of gene expression data that hold tremendous potential for new understanding, leading to advances in functional genomics and molecular biology. Cluster analysis (CA) is an early step in the exploration of such data that is useful for purposes of data reduction, exposing hidden patterns, and the generation of hypotheses regarding the relationship between genes and phenotypes. In this paper we present a new model for the clique partitioning problem and illustrate how it can be used to perform cluster analysis in this setting.     

Was tun Lektoren?

What is the work of editors? Counselling of a ?service in background“The work of editors as employees in publishing houses or as free lancers is a ?service in background“ and hence it is less well-known in comparison with other media professionals. Nevertheless, editors have an important role as intermediary between authors and the reading public. The author delineates the profession of editors and the technical aspects of their work and explains some typical conflicts which may be relevant to a coaching of editors.     

Coaching und Psychotherapie — Differenz und Konvergenz

Coaching and psychotherapy — difference and convergence. A discussion on counseling between professional and personal issuesThe author discusses the relation between coaching and psychotherapy. He emphasises several crucial differences, but here he is concerned with the interfaces between these formats. He demonstrates, that in many cases psychotherapeutic views — basing on corresponding qualifications — may offer an important improvement of coaching. This is illustrated by some case studies.     

Determinanten des Informationsgehalts von Managementprognosen – eine empirische Untersuchung anhand der DAX und MDAX-Unternehmen

In this article the characteristics and determinants of the information content of management earnings forecasts of the German DAX and MDAX companies between 2002 and 2005 are analyzed. As proxy for the information content I use the precision of the wording of a forecast. I can show that the forecasts of MDAX companies are more precisely formulated than those of DAX companies. Furthermore forecasts are formulated more precisely, when companies have, (1) a lower percentage of intangible assets, (2) lower market capitalization, (3) lower volatility of earnings and (4) a higher need for external financing.