Conformal integrals in various dimensions and Clifford groups

Conformal transformations of the Euclidean space of any dimension can be formulated as the M\"obius group in terms of Clifford algebras. Correlation functions of a conformal field theory are expressed in terms of conformal integrals, which furnish solutions to linear systems on the configuration space of points on the Euclidean space. Expressing the conformal integral in terms of a Clifford algebra the linear system is related to toric GKZ systems. Explicit series solutions for conformal integrals are obtained using the power of toric methods as GKZ hypergeometric functions. Partial permutation symmetry of the solutions dictated by the toric method is used to relate the solutions to Feynman trees, or, channels, in field theory parlance.Comment: Largely expanded with conformal integral written explicitly as A-hypergeometric series solutions for GKZ systems for N=4,5,6 points. Symmetry of solutions discussed and connection to channels established. LaTeX 1+20 pages. 2 figure

A Quantitative Model for Human Olfactory Receptors

A wide variety of chemicals having distinct odors are smelled by humans. Odor perception initiates in the nose, where it is detected by a large family of olfactory receptors (ORs). Based on divergence of evolutionary model, a sequence of human ORs database has been proposed by D. Lancet et al (2000, 2006). It is quite impossible to infer whether a given sequence of nucleotides is a human OR or not, without any biological experimental validation. In our perspective, a proper quantitative understanding of these ORs is required to justify or nullify whether a given sequence is a human OR or not. In this paper, all human OR sequences have been quantified, and a set of clusters have been made using the quantitative results based on two different metrics. Using this proposed quantitative model, one can easily make probable justification or deterministic nullification whether a given sequence of nucleotides is a probable human OR homologue or not, without seeking any biological experiment. Of course a further biological experiment is essential to validate the probable human OR homologue

Are cyber-blackouts in service networks likely?: Implications for Aggregate Cyber Risk Management

@TechReport{UCAM-CL-TR-926, author = {Pal, Ranjan and Psounis, Konstantinos and Kumar, Abhishek and Crowcroft, Jon and Hui, Pan and Golubchik, Leana and Kelly, John and Chatterjee, Aritra and Tarkoma, Sasu}, title = {{Are cyber-blackouts in service networks likely?: implications for cyber risk management}}, year = 2018, month = oct, url = {https://www.cl.cam.ac.uk/techreports/UCAM-CL-TR-926.pdf}, institution = {University of Cambridge, Computer Laboratory}, number = {UCAM-CL-TR-926} }Service liability interconnections among networked IT and IoT driven service organizations create potential channels for cascading service disruptions due to modern cybercrimes such as DDoS, APT, and ransomware attacks. The very recent Mirai DDoS and WannaCry ransomware attacks serve as famous examples of cyber-incidents that have caused catastrophic service disruptions worth billions of dollars across organizations around the globe. A natural question that arises in this context is “what is the likelihood of a cyber-blackout?”, where the latter term is defined as: “the probability that all (or a major subset of) organizations in a service chain become dysfunctional in a certain manner due to a cyber-attack at some or all points in the chain”. The answer to this question has major implications to risk management businesses such as cyber-insurance when it comes to designing policies by risk-averse insurers for providing coverage to clients in the aftermath of such catastrophic network events. In this paper, we investigate this question in general as a function of service chain networks and different loss distribution types. We show somewhat surprisingly (and discuss potential practical implications) that following a cyber-attack, the probability of a cyber-blackout and the increase in total service-related monetary losses across all organizations, due to the effect of (a) network interconnections, and (b) a wide range of loss distributions, are mostly very small, regardless of the network structure – the primary rationale behind the results being attributed to degrees of heterogeneity in wealth base among organizations, and Increasing Failure Rate (IFR) property of loss distributions

When Are Cyber Blackouts in Modern Service Networks Likely?: A Network Oblivious Theory on Cyber (Re)Insurance Feasibility

Service liability interconnections among globally networked IT- and IoT-driven service organizations create potential channels for cascading service disruptions worth billions of dollars, due to modern cyber-crimes such as DDoS, APT, and ransomware attacks. A natural question that arises in this context is: What is the likelihood of a cyber-blackout?, where the latter term is defined as the probability that all (or a major subset of) organizations in a service chain become dysfunctional in a certain manner due to a cyber-attack at some or all points in the chain. The answer to this question has major implications to risk management businesses such as cyber-insurance when it comes to designing policies by risk-averse insurers for providing coverage to clients in the aftermath of such catastrophic network events. In this article, we investigate this question in general as a function of service chain networks and different cyber-loss distribution types. We show somewhat surprisingly (and discuss the potential practical implications) that, following a cyber-attack, the effect of (a) a network interconnection topology and (b) a wide range of loss distributions on the probability of a cyber-blackout and the increase in total service-related monetary losses across all organizations are mostly very small. The primary rationale behind these results are attributed to degrees of heterogeneity in the revenue base among organizations and the Increasing Failure Rate property of popular (i.i.d/non-i.i.d) loss distributions, i.e., log-concave cyber-loss distributions. The result will enable risk-averse cyber-riskmanagers to safely infer the impact of cyber-attacks in a worst-case network and distribution oblivious setting.Peer reviewe

Improving Service Level of Free-Floating Bike Sharing Systems

Bike Sharing is a sustainable mode of urban mobility, not only for regular commuters but also for casual users and tourists. Free-floating bike sharing (FFBS) is an innovative bike sharing model, which saves on start-up cost, prevents bike theft, and offers significant opportunities for smart management by tracking bikes in real-time with built-in GPS. Efficient management of a FFBS requires: 1) analyzing its mobility patterns and spatio-temporal imbalance of supply and demand of bikes, 2) developing strategies to mitigate such imbalances, and 3) understanding the causes of a bike getting damaged and developing strategies to minimize them. All of these operational management problems are successfully addressed in this dissertation, using tools from Operations Research, Statistical and Machine Learning and using Share-A-Bull Bike FFBS and Divvy station-based bike sharing system as case studies

Strukturbestimmung von Viscotoxin A1, Tendamistat und Tripeptidyl Peptidase-I

Die vorliegende Arbeit beschreibt sowohl die Methoden, die benutzt wurden, um die Kristallstrukturen der genannten Proteine mithilfe von experimenteller Phasenbestimmung zu lösen, als auch eine Analyse ihrer Struktur.Viscotoxin gehört zur Familie der α- und β-Thionine, die zytotoxische Aktivität aufweist und biologische Membrane aufbrechen kann. The 1,25Å Kristallstruktur von Viscotoxin A1 wurde mithilfe des anomalen Signales der Schwefelatome per SAD ("single wavelength anomalous scattering") mit Daten von einer Drehanodenanlage gelöst. Viscotoxin A1 weist wie viele Viscotoxine die für Thionine typische Tertiärstruktur auf. Eine positiv geladene Tasche, die ein funktionell essentielles Phosphation bindet, fehlt in der Struktur von Viscotoxin A1 wegen einer wahrscheinlichen Fehlordnung. Moleküe der asymmetrischen Einheit bilden Dimere. A1-Kristalle haben einen höheren Lösemittelanteil als andere Viscotoxinstrukturen und bilden einen Lösemittelkanal entlang der 43-Achse.Tendamistat gehört zur Familie der mikrobialen Amylaseinhibitoren. Die 1.5Å Kristallstruktur von Tendamistat wurde mithilfe von SAD gelöst. Dazu wurde das extrem schwache anomale Signal der Schwefelatome mit einer Drehanode gemessen. Tendamistat hat eine Immunoglobulin-ähnliche Tertiärstruktur. Tendamistatmoleküe bilden in der asymmetrischen Einheit einen linearen Tetramer. Man stellt nur kleine Unterschiede in der Hauptkette von Tendamistat im Vergleich zu vormals bestimmten Kristallstrukturen fest. In der Konformation von Seitenketten, die an der Amylaseinhibition beteiligt sind, beobachtet man hingegen Unterschiede. Aufgrund seiner hohen Kristallsymmetrie und dem extrem schwachen anomalen Signal kann Tendamistat als Testkristall genutzt werden, um kristallographische Instrumente zu kalibrieren und Probleme zu erkennen.Die spätinfantile neuronale Ceroid-Lipofuszinose, eine tödliche neurodegenerative Kinderkrankheit wird durch eine Mutation im tpp1-Gen ausgelöst, welches TPP1 kodiert. Kristalle der voll glukosilierten Vorstufe von TPP1 traten unter Bedingungen auf, die einen partiellen autokatalytischen Schnitt zwischen dem Prosegment und der katalystischen Domäne vermuten lassen. Die Struktur von TPP1 wurde mittels MAD ("multiple-wavelength anomalous dispersion") mit einem Selenomethioninderivat gelöst. Die Röntgen-kristallographische Analyse bei einer Auflösung von 2.35Å ergab eine globuläre Struktur mit einer Subtilisin-ähnlichen Faltung, einer S475-E272-D360 katalytischen Triade und einer oktaedrisch koordinierten Ca2+ Bindestelle, die charakteristische Eigenschaften der S53 Familie der sedolisinartigen Peptidasen sind. Im Gegensatz zu anderen S53 Peptidasen weist die TPP1 Struktur sterische Einschränkungen an der P4 Substrattasche auf, welche erklärt, weswegen TPP1 Tripeptide vorzugsweise vom unsubstituierten Aminoende her schneidet