Report on the Dagstuhl Seminar on Visualization and Monitoring of Network Traffic

The Dagstuhl Seminar on Visualization and Monitoring of Network Traffic took place May 17-20, 2009 in Dagstuhl, Germany. Dagstuhl seminars promote personal interaction and open discussion of results as well as new ideas. Unlike at most conferences, the focus is not solely on the presentation of established results but also, and in equal parts, to presentation of results, ideas, sketches, and open problems. The aim of this particular seminar was to bring together experts from the information visualization community and the networking community in order to discuss the state of the art of monitoring and visualization of network traffic. People from the different research communities involved jointly organized the seminar. The co-chairs of the seminar from the networking community were Aiko Pras (University of Twente) and Jürgen Schönwälder (Jacobs University Bremen). The co-chairs from the visualization community were Daniel A. Keim (University of Konstanz) and Pak Chung Wong (Pacific Northwest National Laboratory). Florian Mansmann (University of Konstanz) helped with producing this report. The seminar was organized and supported by Schloss Dagstuhl and the European Network of Excellence for the Management of Internet Technologies and Complex Systems (EMANICS)

Myofascial Trigger Points in Children With Tension-Type Headache: A New Diagnostic and Therapeutic Option

The goal of this pilot study was to evaluate the effect of a trigger point–specific physiotherapy on headache frequency, intensity, and duration in children with episodic or chronic tension-type headache. Patients were recruited from the special headache outpatient clinic. A total of 9 girls (mean age 13.1 years; range, 5-15 years) with the diagnosis of tension-type headache participated in the pilot study from May to September 2006 and received trigger point–specific physiotherapy twice a week by a trained physiotherapist. After an average number of 6.5 therapeutic sessions, the headache frequency had been reduced by 67.7%, intensity by 74.3%, and duration by 77.3%. No side effects were noted during the treatment. These preliminary findings suggest a role for active trigger points in children with tension-type headache. Trigger point–specific physiotherapy seems to be an effective therapy in these children. Further prospective and controlled studies in a larger cohort are warranted

Gender-Specific Differences in Low-Dose Haloperidol Response for Prevention of Postoperative Nausea and Vomiting: A Register-Based Cohort Study

Postoperative nausea and vomiting (PONV) is one of the most common and distressing complications after general anesthesia and surgery, with young non-smoking females receiving postoperative opioids being high-risk patients. This register-based study aims to evaluate the effect of low-dose haloperidol (0.5 mg intravenously) directly after induction of general anesthesia to reduce the incidence of PONV in the postoperative anesthesiological care unit (PACU).Multivariable regression models were used to investigate the association between low-dose haloperidol and the occurrence of PONV using a patient registry containing 2,617 surgical procedures carried out at an university hospital.Haloperidol 0.5 mg is associated with a reduced risk of PONV in the total collective (adjusted odds ratio = 0.75, 95% confidence interval: [0.56, 0.99], p = 0.05). The results indicate that there is a reduced risk in male patients (adjusted odds ratio = 0.45, 95% confidence interval: [0.28, 0.73], p = 0.001) if a dose of 0.5 mg haloperidol was administered while there seems to be no effect in females (adjusted odds ratio = 1.02, 95% confidence interval: [0.71, 1.46], p = 0.93). Currently known risk factors for PONV such as female gender, duration of anesthesia and the use of opioids were confirmed in our analysis.This study suggests that low-dose haloperidol has an antiemetic effect in male patients but has no effect in female patients. A confirmation of the gender-specific effects we have observed in this register-based cohort study might have major implications on clinical daily routine

Acupuncture in acute herpes zoster pain therapy (ACUZoster) - design and protocol of a randomised controlled trial

Background: Acute herpes zoster is a prevalent condition. One of its major symptoms is pain, which can highly influence patient's quality of life. Pain therapy is limited. Acupuncture is supposed to soften neuropathic pain conditions and might therefore act as a therapeutic alternative. Objective of the present study is to investigate whether a 4 week semi-standardised acupuncture is non-inferior to sham laser acupuncture and the anticonvulsive drug gabapentine in the treatment of pain associated with herpes zoster. Methods/Design: Three-armed, randomised, placebo-controlled trial with a total follow-up time of 6 months. Up to estimated 336 patients (interim analyses) with acute herpes zoster pain (VAS > 30 mm) will be randomised to one of three groups (a) semi-standardised acupuncture (168 patients); (b) gabapentine with individualised dosage between 900-3600 mg/d (84 patients); (c) sham laser acupuncture. Intervention takes place over 4 weeks, all patients will receive analgesic therapy (non-opioid analgesics: metamizol or paracetamol and opioids: tramadol or morphine). Therapy phase includes 4 weeks in which group (a) and (c) consist of 12 sessions per patient, (b) visits depend on patients needs. Main outcome measure is to assess the alteration of pain intensity before and 1 week after treatment sessions (visual analogue scale VAS 0-100 mm). Secondary outcome measure are: alteration of pain intensity and frequency of pain attacks; alteration of different aspects of pain evaluated by standardised pain questionnaires (NPI, PDI, SES); effects on quality of life (SF 36); analgesic demand; alteration of sensoric perception by systematic quantitative sensory testing (QST); incidence of postherpetic neuralgia; side effects and cost effectiveness. Credibility of treatments will be assessed. Discussion: This study is the first large-scale randomised placebo controlled trial to evaluate the efficacy of acupuncture compared to gabapentine and sham treatment and will provide valuable new information about the clinical and physiological effects of acupuncture and gabapentine in the treatment of acute herpes zoster pain. The study has been pragmatically designed to ensure that the study findings can be implemented into clinical practice if acupuncture can be shown to be an effective treatment strategy in acute herpes zoster pain

Visuelle Analyse von Netzwerkverkehr - Interaktives Monitoring, Entdeckung und Interpretation von Sicherheitsbedrohungen

Das Internet ist ein gefährlicher Ort geworden: Schadcode breitet sich auf PCs auf der ganzen Welt aus und schafft damit sogenannte Botnets, welche jederzeit bereit sind, die Netzwerkinfrastruktur anzugreifen. Netzwerkverkehr zu überwachen und den Überblick über die gewaltige Anzahl von sicherheitsrelevanten Vorfällen oder Anomalien im Netzwerk zu behalten sind schwierige Aufgaben. Während Monitoring- und Intrusion-Detection-Systeme weit verbreitet sind, um operationale Daten in Echtzeit zu erheben, sind Bemühungen, ihren Output auf detaillierter Ebene manuell zu analysieren, oftmals ermüdend, benötigen viel Personal, oder schlagen vollständig fehl, die notwendigen Einsichten zu liefern aufgrund der Komplexität und des Volumens der zugrunde liegenden Daten.Diese Dissertation stellt ein Bestreben dar, automatische Überwachungs- und Intrusion-Detection-Systeme durch visuelle Explorationsschnittstellen zu ergänzen, welche menschliche Analysten befähigen, tiefere Einsichten in riesige, komplexe und sich dynamisch verändernde Datensätze zu gewinnen. In diesem Zusammenhang ist ein Hauptanliegen von visueller Analyse, bestehende Visualisierungsmethoden zu verfeinern, um ihre Skalierbarkeit in Bezug auf a) die Datenmenge, b) visuelle Beschränkungen von Computerbildschirmen und c) die Aufnahmefähigkeit der menschlichen Wahrnehmung zu verbessern. Darüber hinaus ist die Entwicklung von innovativen Visualisierungsmetaphern ein weiteres Hauptanliegen dieser Doktorarbeit. Insbesondere beschäftigt sich diese Dissertation mit skalierbaren Visualisierungstechniken für detaillierte Analyse von riesigen Netzwerk-Zeitreihen. Indem Zeitreihen einerseits in Pixelvisualisierungen anhand ihrer logischen Intervalle gruppiert werden und andererseits zur verbesserten Abgrenzung eingefärbt werden, erlauben unsere Methoden genaue Vergleiche von temporären Aspekten in Netzwerk-Sicherheits-Datensätzen.Um die Eigenheiten von Netzwerkverkehr und verteilten Attacken in Bezug auf die Verteilung der beteiligten Rechner aufzudecken, wird eine hierarchische Karte des IP Adressraums vorgeschlagen, welche sowohl geographische als auch topologische Aspekte des Internets berücksichtigt. Da naives Verbinden der wichtigsten Kommunikationspartner auf der Karte zu störenden visuellen Artefakten führen würde, können Hierarchical Edge Bundles dazu verwendet werden, die Verkehrsverbindungen anhand der Hierarchie der Karte zu gruppieren, um dadurch eine skalierbarere Analyse der Kommunikationspartner zu ermöglichen.Ferner wird die Karte durch eine multivariate Analysetechnik ergänzt, um auf visuelle Art und Weise die multidimensionale Natur des Netzwerkverkehrs und der Daten von sicherheitsrelevanten Vorfällen zu studieren. Insbesondere deckt die Interkation der implementierten Prototypen die Eignung der vorgeschlagenen Visualisierungsmethoden auf, einen Überblick zu verschaffen, Kommunikationspartner zuzuordnen, in interessante Regionen hineinzuzoomen, und detaillierte Informationen abzufragen. Für eine noch detailliertere Analyse der Rechner im Netzwerk, führen wir einen graphenbasierten Ansatz ein, um Veränderungen im Verhalten von Rechnern und abstrakteren Einheiten im Netzwerk zu beobachten. Diese Art von Information ist insbesondere nützlich, um Fehlverhalten der Rechner innerhalb der lokalen Netzwerkinfrastruktur aufzudecken, welche andernfalls die Sicherheit des Netzwerks beträchtlich gefährden können.Um die umfassende Sicht auf Netzwerkverkehr abzurunden, wurde eine Self-Organizing Map dazu verwendet, die Eignung der Visualisierungsmethoden zur Analyse nicht nur von strukturierten Daten der Netzwerkprotokolle, sondern auch von unstrukturierten Informationen, wie beispielsweise dem textuellen Kontext von Email Nachrichten, zu demonstrieren. Mittels der Extraktion der charakteristischen Eigenschaften aus den Emails, gruppiert der Neuronale-Netzwerk-Algorithmus ähnliche Emails und ist imstande, bis zu einem gewissen Grad zwischen Spam und legitimen Emails zu unterscheiden.Im Rahmen dieser Dissertation demonstrieren die präsentierten Prototypen die breite Anwendbarkeit der vorgeschlagenen Visualisierungsmethoden in zahlreichen Fallstudien und legen ihr unerschöpfliches Potential dar, in Kombination mit automatischen Intrusion-Detection-Methoden verwendet zu werden. Deswegen sind wir zuversichtlich, dass Visual-Analytics-Anwendungen in den Bereichen Netzwerküberwachung und -sicherheit schnell ihren Weg aus der Forschung in die Praxis finden werden, indem sie menschliches Hintergrundwissen und Intelligenz mit der Geschwindigkeit und Genauigkeit von Computern kombinieren

Visual analysis of e-mail traffic

Diese Arbeit beschreibt Methoden zur visuellen geographischen Analyse von E-mail Verkehr.Aus dem Header einer E-mail können Hostadressen und IP-Adressen herausgefiltert werden. Anhand einer Datenbank werden diesen Host- und IP-Adressen geographische Koordinaten zugeordnet.Durch eine Visualisierung werden in übersichtlicher Art und Weise mehrere tausend E-mail Routen dargestellt. Zusätzlich dazu wurden interktive Manipulationsmöglichkeiten vorgestellt, welche eine visuelle Exploration der Daten ermöglichen.Ferner werden in dieser Arbeit die geographischen Unterschiede zwischen Spam E-mail Routen und normalen E-mail Routen herausgearbeitet

Interactive Exploration of Data Traffic with Hierarchical Network Maps

Network communication has become indispensable in business, education, and government. With the pervasive role of the Internet as a means of sharing information across networks, its misuse for destructive purposes, such as spreading malicious code, compromising remote hosts or damaging data through unauthorized access, has grown immensely in the recent years. The classical way of monitoring the operation of large network systems is by analyzing the system logs for detecting anomalies. In this work, we introduce Hierarchical Network Map, an interactive visualization technique for gaining a deeper insight into network flow behavior by means of user-driven visual exploration. Our approach is meant as an enhancement to conventional analysis methods based on statistics or machine learning. We use multidimensional modeling combined with position and display awareness to view source and target data of the hosts in a hierarchical fashion with the ability to interactively change the level of aggregation or apply filtering. The interdisciplinary approach integrating data warehouse technology, information visualization, and decision support, brings about the benefit of efficiently collecting the input data and aggregating over very large data sets, visualizing the results, and providing interactivity to facilitate analytical reasoning

From analysis to interactive exploration: Building visual hierarchies from OLAP cubes

Abstract. We present a novel framework for comprehensive exploration of OLAP data by means of user-defined dynamic hierarchical visualizations. The multidimensional data model behind the OLAP architecture is particularly suitable for sophisticated analysis of large data volumes. However, the ultimate benefit of applying OLAP technology depends on the “intelligence ” and usability of visual tools available to end-users. The explorative framework of our proposed interface consists of the navigation structure, a selection of hierarchical visualization techniques, and a set of interaction features. The navigation interface allows users to pursue arbitrary disaggregation paths within single data cubes and, more importantly, across multiple cubes. In the course of interaction, the navigation view adapts itself to display the chosen path and the options valid in the current context. Special effort has been invested in handling non-trivial relationships (e.g., mixed granularity) within hierarchical dimensions in a way transparent to the user. We propose a visual structure called Enhanced Decomposition Tree to to be used along with popular “state-of-the-art ” hierarchical visualization techniques. Each level of the tree is produced by a disaggregation step, whereas the nodes display the specified subset of measures, either as plain numbers or as an embedded chart. The proposed technique enables a stepwise descent towards the desired level of detail while preserving the history of the interaction. Aesthetic hierarchical layout of the node-link tree ensures clear structural separation between the analyzed values embedded in the nodes and their dimensional characteristics which label the links. Our framework provides an intuitive and powerful interface for exploring complex multidimensional data sets.

Towards readable layouts for modeling data warehouses

Data warehouses are large-scale databases that are usually managed by means of diagram-based conceptual models. However, the complexity of those models often imposes significant design challenges. In particular, this article studies their different underlying graph layouts. The working hypothesis is that graph layouts influence diagram readability, with the latter being significant for facilitating the design process. We define the main viewpoints involved in conceptual modeling. For each one, surveyed as well as alternative layouts were evaluated against a set of aesthetics and efficiency measures. As a result, more readable graph layouts than those found in the literature were identified