@article{JuergensenKonstantinidis2006, author = {J{\"u}rgensen, Helmut and Konstantinidis, Stavros}, title = {(Near-)inverses of sequences}, issn = {0020-7160}, doi = {10.1080/00207160500537801}, year = {2006}, abstract = {We introduce the notion of a near-inverse of a non-decreasing sequence of positive integers; near-inverses are intended to assume the role of inverses in cases when the latter cannot exist. We prove that the near-inverse of such a sequence is unique; moreover, the relation of being near-inverses of each other is symmetric, i.e. if sequence g is the near-inverse of sequence f, then f is the near-inverse of g. There is a connection, by approximations, between near- inverses of sequences and inverses of continuous strictly increasing real-valued functions which can be exploited to derive simple expressions for near-inverses}, language = {en} } @article{KawanabeBlanchardSugiyamaetal.2006, author = {Kawanabe, Motoaki and Blanchard, Gilles and Sugiyama, Masashi and Spokoiny, Vladimir G. and M{\"u}ller, Klaus-Robert}, title = {A novel dimension reduction procedure for searching non-Gaussian subspaces}, issn = {0302-9743}, doi = {10.1007/11679363_19}, year = {2006}, abstract = {In this article, we consider high-dimensional data which contains a low-dimensional non-Gaussian structure contaminated with Gaussian noise and propose a new linear method to identify the non-Gaussian subspace. Our method NGCA (Non-Gaussian Component Analysis) is based on a very general semi-parametric framework and has a theoretical guarantee that the estimation error of finding the non-Gaussian components tends to zero at a parametric rate. NGCA can be used not only as preprocessing for ICA, but also for extracting and visualizing more general structures like clusters. A numerical study demonstrates the usefulness of our method}, language = {en} } @article{DelgrandeSchaubTompits2006, author = {Delgrande, James Patrick and Schaub, Torsten H. and Tompits, Hans}, title = {A Preference-Based Framework for Updating logic Programs : preliminary reports}, year = {2006}, language = {en} } @article{DelgrandeSchaubTompits2006, author = {Delgrande, James Patrick and Schaub, Torsten H. and Tompits, Hans}, title = {An Extended Query language for action languages (and its application to aggregates and preferences)}, year = {2006}, language = {en} } @article{AngerGebserSchaub2006, author = {Anger, Christian and Gebser, Martin and Schaub, Torsten H.}, title = {Approaching the core of unfounded sets}, year = {2006}, language = {en} } @article{CordesKaiserSelbig2006, author = {Cordes, Frank and Kaiser, Rolf and Selbig, Joachim}, title = {Bioinformatics approach to predicting HIV drug resistance}, issn = {1473-7159}, doi = {10.1586/14737159.6.2.207}, year = {2006}, abstract = {The emergence of drug resistance remains one of the most challenging issues in the treatment of HIV-1 infection. The extreme replication dynamics of HIV facilitates its escape from the selective pressure exerted by the human immune system and by the applied combination drug therapy. This article reviews computational methods whose combined use can support the design of optimal antiretroviral therapies based on viral genotypic and phenotypic data. Genotypic assays are based on the analysis of mutations associated with reduced drug susceptibility, but are difficult to interpret due to the numerous mutations and mutational patterns that confer drug resistance. Phenotypic resistance or susceptibility can be experimentally evaluated by measuring the inhibition of the viral replication in cell culture assays. However, this procedure is expensive and time consuming}, language = {en} } @article{MeinelWang2006, author = {Meinel, Christoph and Wang, Long}, title = {Building content clusters based on modelling page pairs}, doi = {10.1007/11610113_85}, year = {2006}, abstract = {We give a new view on building content clusters from page pair models. We measure the heuristic importance within every two pages by computing the distance of their accessed positions in usage sessions. We also compare our page pair models with the classical pair models used in information theories and natural language processing, and give different evaluation methods to build the reasonable content communities. And we finally interpret the advantages and disadvantages of our models from detailed experiment results}, language = {en} } @article{PerniciWeske2006, author = {Pernici, Barbara and Weske, Mathias}, title = {Business process management}, issn = {0169-023X}, year = {2006}, language = {en} } @article{GerbserSchaub2006, author = {Gerbser, Martin and Schaub, Torsten H.}, title = {Characterizing (ASP) inferences by unit propagation}, year = {2006}, language = {en} } @article{DelgrandeLiuSchaubetal.2006, author = {Delgrande, James Patrick and Liu, Daphne H. and Schaub, Torsten H. and Thiele, Sven}, title = {COBA 2.0 : a consistency-based belief change system}, year = {2006}, language = {en} } @article{DornhegeBlankertzKrauledatetal.2006, author = {Dornhege, Guido and Blankertz, Benjamin and Krauledat, Matthias and Losch, Florian and Curio, Gabriel and M{\"u}ller, Klaus-Robert}, title = {Combined optimization of spatial and temporal filters for improving brain-computer interfacing}, series = {IEEE transactions on bio-medical electronics}, volume = {53}, journal = {IEEE transactions on bio-medical electronics}, number = {11}, publisher = {IEEE}, address = {New York}, issn = {0018-9294}, doi = {10.1109/TBME.2006.883649}, pages = {2274 -- 2281}, year = {2006}, abstract = {Brain-computer interface (BCI) systems create a novel communication channel from the brain to an output de ice by bypassing conventional motor output pathways of nerves and muscles. Therefore they could provide a new communication and control option for paralyzed patients. Modern BCI technology is essentially based on techniques for the classification of single-trial brain signals. Here we present a novel technique that allows the simultaneous optimization of a spatial and a spectral filter enhancing discriminability rates of multichannel EEG single-trials. The evaluation of 60 experiments involving 22 different subjects demonstrates the significant superiority of the proposed algorithm over to its classical counterpart: the median classification error rate was decreased by 11\%. Apart from the enhanced classification, the spatial and/or the spectral filter that are determined by the algorithm can also be used for further analysis of the data, e.g., for source localization of the respective brain rhythms.}, language = {en} } @article{RozinatVanderAalst2006, author = {Rozinat, A and Van der Aalst, Wil M. P.}, title = {Conformance testing: Measuring the fit and appropriateness of event logs and process models}, year = {2006}, abstract = {Most information systems log events (e.g., transaction logs, audit traits) to audit and monitor the processes they support. At the same time, many of these processes have been explicitly modeled. For example, SAP R/3 logs events in transaction logs and there are EPCs (Event-driven Process Chains) describing the so-called reference models. These reference models describe how the system should be used. The coexistence of event logs and process models raises an interesting question: "Does the event log conform to the process model and vice versa?". This paper demonstrates that there is not a simple answer to this question. To tackle the problem, we distinguish two dimensions of conformance: fitness (the event log may be the result of the process modeled) and appropriateness (the model is a likely candidate from a structural and behavioral point of view). Different metrics have been defined and a Conformance Checker has been implemented within the ProM Framework}, language = {en} } @article{GerbserLeeLierler2006, author = {Gerbser, Martin and Lee, Joohyung and Lierler, Yuliya}, title = {Elementary sets for logic programs}, isbn = {978-1-57735-281-5}, year = {2006}, language = {en} } @article{LemmCurioHlushchuketal.2006, author = {Lemm, Steven and Curio, Gabriel and Hlushchuk, Yevhen and M{\"u}ller, Klaus-Robert}, title = {Enhancing the signal-to-noise ratio of ICA-based extracted ERPs}, issn = {0018-9294}, doi = {10.1109/Tbme.2006.870258}, year = {2006}, abstract = {When decomposing single trial electroencephalography it is a challenge to incorporate prior physiological knowledge. Here, we develop a method that uses prior information about the phase-locking property of event-related potentials in a regularization framework to bias a blind source separation algorithm toward an improved separation of single-trial phase-locked responses in terms of an increased signal-to-noise ratio. In particular, we suggest a transformation of the data, using weighted average of the single trial and trial-averaged response, that redirects the focus of source separation methods onto the subspace of event-related potentials. The practical benefit with respect to an improved separation of such components from ongoing background activity and extraneous noise is first illustrated on artificial data and finally verified in a real-world application of extracting single-trial somatosensory evoked potentials from multichannel EEG-recordings}, language = {en} } @article{MileoSchaub2006, author = {Mileo, Alessandra and Schaub, Torsten H.}, title = {Extending ordered disjunctions for policy enforcement : preliminary report}, year = {2006}, language = {en} } @article{HarmelingDornhegeTaxetal.2006, author = {Harmeling, Stefan and Dornhege, Guido and Tax, David and Meinecke, Frank C. and M{\"u}ller, Klaus-Robert}, title = {From outliers to prototypes : Ordering data}, issn = {0925-2312}, doi = {10.1016/j.neucom.2005.05.015}, year = {2006}, abstract = {We propose simple and fast methods based on nearest neighbors that order objects from high-dimensional data sets from typical points to untypical points. On the one hand, we show that these easy-to-compute orderings allow us to detect outliers (i.e. very untypical points) with a performance comparable to or better than other often much more sophisticated methods. On the other hand, we show how to use these orderings to detect prototypes (very typical points) which facilitate exploratory data analysis algorithms such as noisy nonlinear dimensionality reduction and clustering. Comprehensive experiments demonstrate the validity of our approach.}, language = {en} } @article{KonczakLinkeSchaub2006, author = {Konczak, Kathrin and Linke, Thomas and Schaub, Torsten H.}, title = {Graphs and colorings for answer set programming}, issn = {1471-0684}, doi = {10.1017/S1471068405002528}, year = {2006}, abstract = {We investigate the usage of rule dependency graphs and their colorings for characterizing and computing answer sets of logic programs. This approach provides us with insights into the interplay between rules when inducing answer sets. We start with different characterizations of answer sets in terms of totally colored dependency graphs that differ ill graph-theoretical aspects. We then develop a series of operational characterizations of answer sets in terms of operators on partial colorings. In analogy to the notion of a derivation in proof theory, our operational characterizations are expressed as (non-deterministically formed) sequences of colorings, turning an uncolored graph into a totally colored one. In this way, we obtain an operational framework in which different combinations of operators result in different formal properties. Among others, we identify the basic strategy employed by the noMoRe system and justify its algorithmic approach. Furthermore, we distinguish operations corresponding to Fitting's operator as well as to well-founded semantics}, language = {en} } @article{HallamaLuckowSchnor2006, author = {Hallama, Nicole and Luckow, Andr{\´e} and Schnor, Bettina}, title = {Grid Security for Fault Tolerant Grid Applications}, isbn = {978-1-880843-60-4}, year = {2006}, language = {en} } @article{LaskovGehlKruegeretal.2006, author = {Laskov, Pavel and Gehl, Christian and Kr{\"u}ger, Stefan and M{\"u}ller, Klaus-Robert}, title = {Incremental support vector learning: analysis, implementation and applications}, series = {Journal of machine learning research}, volume = {7}, journal = {Journal of machine learning research}, publisher = {MIT Press}, address = {Cambridge, Mass.}, issn = {1532-4435}, pages = {1909 -- 1936}, year = {2006}, abstract = {Incremental Support Vector Machines (SVM) are instrumental in practical applications of online learning. This work focuses on the design and analysis of efficient incremental SVM learning, with the aim of providing a fast, numerically stable and robust implementation. A detailed analysis of convergence and of algorithmic complexity of incremental SVM learning is carried out. Based on this analysis, a new design of storage and numerical operations is proposed, which speeds up the training of an incremental SVM by a factor of 5 to 20. The performance of the new algorithm is demonstrated in two scenarios: learning with limited resources and active learning. Various applications of the algorithm, such as in drug discovery, online monitoring of industrial devices and and surveillance of network traffic, can be foreseen.}, language = {en} } @article{BordihnFernauHolzeretal.2006, author = {Bordihn, Henning and Fernau, Henning and Holzer, Markus and Manca, Vincenzo and Martin-Vide, Carlos}, title = {Iterated sequential transducers as language generating devices}, series = {Theoretical computer science}, volume = {369}, journal = {Theoretical computer science}, number = {1}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0304-3975}, doi = {10.1016/j.tcs.2006.07.059}, pages = {67 -- 81}, year = {2006}, abstract = {Iterated finite state sequential transducers are considered as language generating devices. The hierarchy induced by the size of the state alphabet is proved to collapse to the fourth level. The corresponding language families are related to the families of languages generated by Lindenmayer systems and Chomsky grammars. Finally, some results on deterministic and extended iterated finite state transducers are established.}, language = {en} } @article{FriedrichKrahmerSchneidenbachetal.2006, author = {Friedrich, Sven and Krahmer, Sebastian and Schneidenbach, Lars and Schnor, Bettina}, title = {Loaded: Server Load Balancing for IPv6}, isbn = {0-7695-2622-5}, year = {2006}, abstract = {With the next generation Internet protocol IPv6 at the horizon, it is time to think about how applications can migrate to IPv6. Web traffic is currently one of the most important applications in the Internet. The increasing popularity of dynamically generated content on the World Wide Web, has created the need for fast web servers. Server clustering together with server load balancing has emerged as a promising technique to build scalable web servers. The paper gives a short overview over the new features of IPv6 and different server load balancing technologies. Further, we present and evaluate Loaded, an user-space server load balancer for IPv4 and IPv6 based on Linux.}, language = {en} } @article{LuckowSchnor2006, author = {Luckow, Andr{\´e} and Schnor, Bettina}, title = {Migol : a Fault Tolerant Service Framework for Grid Computing : Evolution to WSRF (2006)}, year = {2006}, language = {en} } @article{GrellSchaubSelbig2006, author = {Grell, Susanne and Schaub, Torsten H. and Selbig, Joachim}, title = {Modelling biological networks by action languages via set programming}, issn = {0302-9743}, doi = {10.1007/11799573}, year = {2006}, language = {en} } @article{OcheretnijGoesselSogomonyanetal.2006, author = {Ocheretnij, Vitalij and G{\"o}ssel, Michael and Sogomonyan, Egor S. and Marienfeld, Daniel}, title = {Modulo p=3 checking for a carry select adder}, doi = {10.1007/s10836-006-6260-8}, year = {2006}, abstract = {In this paper a self-checking carry select adder is proposed. The duplicated adder blocks which are inherent to a carry select adder without error detection are checked modulo 3. Compared to a carry select adder without error detection the delay of the MSB of the sum of the proposed adder does not increase. Compared to a self-checking duplicated carry select adder the area is reduced by 20\%. No restrictions are imposed on the design of the adder blocks}, language = {en} } @article{GressmannJanhunenMerceretal.2006, author = {Gressmann, Jean and Janhunen, Tomi and Mercer, Robert E. and Schaub, Torsten H. and Thiele, Sven and Tichy, Richard}, title = {On probing and multi-threading in platypus}, year = {2006}, language = {en} } @article{GressmannJanhunenMerceretal.2006, author = {Gressmann, Jean and Janhunen, Tomi and Mercer, Robert E. and Schaub, Torsten H. and Thiele, Sven and Tichy, Richard}, title = {On probing and multi-threading in platypus}, year = {2006}, language = {en} } @article{LaubRothBuhmannetal.2006, author = {Laub, Julian and Roth, Volker and Buhmann, Joachim and M{\"u}ller, Klaus-Robert}, title = {On the information and representation of non-Euclidean pairwise data}, issn = {0031-3203}, doi = {10.1016/j.patcog.2006.04.016}, year = {2006}, abstract = {Two common data representations are mostly used in intelligent data analysis, namely the vectorial and the pairwise representation. Pairwise data which satisfy the restrictive conditions of Euclidean spaces can be faithfully translated into a Euclidean vectorial representation by embedding. Non-metric pairwise data with violations of symmetry, reflexivity or triangle inequality pose a substantial conceptual problem for pattern recognition since the amount of predictive structural information beyond what can be measured by embeddings is unclear. We show by systematic modeling of non-Euclidean pairwise data that there exists metric violations which can carry valuable problem specific information. Furthermore, Euclidean and non-metric data can be unified on the level of structural information contained in the data. Stable component analysis selects linear subspaces which are particularly insensitive to data fluctuations. Experimental results from different domains support our pattern recognition strategy.}, language = {en} } @article{BordihnHolzer2006, author = {Bordihn, Henning and Holzer, Markus}, title = {Programmed grammars and their relation to the LBA problem}, series = {Acta informatica}, volume = {43}, journal = {Acta informatica}, publisher = {Elsevier}, address = {New York}, issn = {0001-5903}, doi = {10.1007/s00236-006-0017-9}, pages = {223 -- 242}, year = {2006}, abstract = {We consider generating and accepting programmed grammars with bounded degree of non-regulation, that is, the maximum number of elements in success or in failure fields of the underlying grammar. In particular, it is shown that this measure can be restricted to two without loss of descriptional capacity, regardless of whether arbitrary derivations or left-most derivations are considered. Moreover, in some cases, precise characterizations of the linear bounded automaton problem in terms of programmed grammars are obtained. Thus, the results presented in this paper shed new light on some longstanding open problem in the theory of computational complexity.}, language = {en} } @article{WilligMitschke2006, author = {Willig, Andreas and Mitschke, Robert}, title = {Results of bit error measurements with sensor nodes and casuistic consequences for design of energy-efficient error control schemes}, isbn = {978-3-540-32158-3}, year = {2006}, abstract = {For the proper design of energy-efficient error control schemes some insight into channel error patterns is needed. This paper presents bit error and packet loss measurements taken with sensor nodes running the popular RFM}, language = {en} } @article{GerbserSchaub2006, author = {Gerbser, Martin and Schaub, Torsten H.}, title = {Tableau calculi for answer set programming}, issn = {0302-9743}, doi = {10.1007/11799573}, year = {2006}, language = {en} } @article{BlankertzMuellerKrusienskietal.2006, author = {Blankertz, Benjamin and M{\"u}ller, Klaus-Robert and Krusienski, Dean and Schalk, Gerwin and Wolpaw, Jonathan R. and Schl{\"o}gl, Alois and Pfurtscheller, Gert and Millan, Jos{\´e} del R. and Schr{\"o}der, Michael and Birbaumer, Niels}, title = {The BCI competition III : validating alternative approaches to actual BCI problems}, issn = {1534-4320}, doi = {10.1109/Tnsre.2006.875642}, year = {2006}, abstract = {A brain-computer interface (BCI) is a system that allows its users to control external devices with brain activity. Although the proof-of-concept was given decades ago, the reliable translation of user intent into device control commands is still a major challenge. Success requires the effective interaction of two adaptive controllers: the user's brain, which produces brain activity that encodes intent, and the BCI system, which translates that activity into device control commands. In order to facilitate this interaction, many laboratories are exploring a variety of signal analysis techniques to improve the adaptation of the BCI system to the user. In the literature, many machine learning and pattern classification algorithms have been reported to give impressive results when applied to BCI data in offline analyses. However, it is more difficult to evaluate their relative value for actual online use. BCI data competitions have been organized to provide objective formal evaluations of alternative methods. Prompted by the great interest in the first two BCI Competitions, we organized the third BCI Competition to address several of the most difficult and important analysis problems in BCI research. The paper describes the data sets that were provided to the competitors and gives an overview of the results.}, language = {en} } @article{BlankertzDornhegeKrauledatetal.2006, author = {Blankertz, Benjamin and Dornhege, Guido and Krauledat, Matthias and M{\"u}ller, Klaus-Robert and Kunzmann, Volker and Losch, Florian and Curio, Gabriel}, title = {The Berlin brain-computer interface : EEG-based communication without subject training}, issn = {1534-4320}, doi = {10.1109/Tnsre.2006.875557}, year = {2006}, abstract = {The Berlin Brain-Computer Interface (BBCI) project develops a noninvasive BCI system whose key features are 1) the use of well-established motor competences as control paradigms, 2) high-dimensional features from 128-channel electroencephalogram (EEG), and 3) advanced machine learning techniques. As reported earlier, our experiments demonstrate that very high information transfer rates can be achieved using the readiness potential (RP) when predicting the laterality of upcoming left-versus right-hand movements in healthy subjects. A more recent study showed that the RP similarily accompanies phantom movements in arm amputees, but the signal strength decreases with longer loss of the limb. In a complementary approach, oscillatory features are used to discriminate imagined movements (left hand versus right hand versus foot). In a recent feedback study with six healthy subjects with no or very little experience with BCI control, three subjects achieved an information transfer rate above 35 bits per minute (bpm), and further two subjects above 24 and 15 bpm, while one subject could not achieve any BCI control. These results are encouraging for an EEG-based BCI system in untrained subjects that is independent of peripheral nervous system activity and does not rely on evoked potentials even when compared to results with very well-trained subjects operating other BCI systems}, language = {en} } @article{MeinelKlotz2006, author = {Meinel, Christoph and Klotz, Volker}, title = {The first 10 years of the ECCC digital library}, doi = {10.1145/1107458.1107484}, year = {2006}, language = {en} } @article{ShenoyKrauledatBlankertzetal.2006, author = {Shenoy, Pradeep and Krauledat, Matthias and Blankertz, Benjamin and Rao, Rajesh P. N. and M{\"u}ller, Klaus-Robert}, title = {Towards adaptive classification for BCI}, doi = {10.1088/1741-2560/3/1/R02}, year = {2006}, abstract = {Non-stationarities are ubiquitous in EEG signals. They are especially apparent in the use of EEG-based brain- computer interfaces (BCIs): (a) in the differences between the initial calibration measurement and the online operation of a BCI, or (b) caused by changes in the subject's brain processes during an experiment (e.g. due to fatigue, change of task involvement, etc). In this paper, we quantify for the first time such systematic evidence of statistical differences in data recorded during offline and online sessions. Furthermore, we propose novel techniques of investigating and visualizing data distributions, which are particularly useful for the analysis of (non-) stationarities. Our study shows that the brain signals used for control can change substantially from the offline calibration sessions to online control, and also within a single session. In addition to this general characterization of the signals, we propose several adaptive classification schemes and study their performance on data recorded during online experiments. An encouraging result of our study is that surprisingly simple adaptive methods in combination with an offline feature selection scheme can significantly increase BCI performance}, language = {en} } @article{SteuerHumburgSelbig2006, author = {Steuer, Ralf and Humburg, Peter and Selbig, Joachim}, title = {Validation and functional annotation of expression-based clusters based on gene ontology}, series = {BMC bioinformatics}, volume = {7}, journal = {BMC bioinformatics}, number = {380}, publisher = {BioMed Central}, address = {London}, issn = {1471-2105}, doi = {10.1186/1471-2105-7-380}, pages = {12}, year = {2006}, abstract = {Background: The biological interpretation of large-scale gene expression data is one of the paramount challenges in current bioinformatics. In particular, placing the results in the context of other available functional genomics data, such as existing bio-ontologies, has already provided substantial improvement for detecting and categorizing genes of interest. One common approach is to look for functional annotations that are significantly enriched within a group or cluster of genes, as compared to a reference group. Results: In this work, we suggest the information-theoretic concept of mutual information to investigate the relationship between groups of genes, as given by data-driven clustering, and their respective functional categories. Drawing upon related approaches (Gibbons and Roth, Genome Research 12: 1574-1581, 2002), we seek to quantify to what extent individual attributes are sufficient to characterize a given group or cluster of genes. Conclusion: We show that the mutual information provides a systematic framework to assess the relationship between groups or clusters of genes and their functional annotations in a quantitative way. Within this framework, the mutual information allows us to address and incorporate several important issues, such as the interdependence of functional annotations and combinatorial combinations of attributes. It thus supplements and extends the conventional search for overrepresented attributes within a group or cluster of genes. In particular taking combinations of attributes into account, the mutual information opens the way to uncover specific functional descriptions of a group of genes or clustering result. All datasets and functional annotations used in this study are publicly available. All scripts used in the analysis are provided as additional files.}, language = {en} } @article{Konczak2006, author = {Konczak, Kathrin}, title = {Voting Theory in Answer Set Programming}, year = {2006}, language = {en} } @article{Konczak2006, author = {Konczak, Kathrin}, title = {Weak order equivalence for Logic Programs with Prefernces}, year = {2006}, language = {en} } @article{AngerGebserJanhunenetal.2006, author = {Anger, Christian and Gebser, Martin and Janhunen, Tomi and Schaub, Torsten H.}, title = {What's a head without a body?}, year = {2006}, language = {en} }