The probability density function of a hardware performance parameter

Probability density function of hardware performance parameter and incentive contractin

Smart Computer Security Audit: Reinforcement Learning with a Deep Neural Network Approximator

A significant challenge in modern computer security is the growing skill gap as intruder capabilities increase, making it necessary to begin automating elements of penetration testing so analysts can contend with the growing number of cyber threats. In this paper, we attempt to assist human analysts by automating a single host penetration attack. To do so, a smart agent performs different attack sequences to find vulnerabilities in a target system. As it does so, it accumulates knowledge, learns new attack sequences and improves its own internal penetration testing logic. As a result, this agent (AgentPen for simplicity) is able to successfully penetrate hosts it has never interacted with before. A computer security administrator using this tool would receive a comprehensive, automated sequence of actions leading to a security breach, highlighting potential vulnerabilities, and reducing the amount of menial tasks a typical penetration tester would need to execute. To achieve autonomy, we apply an unsupervised machine learning algorithm, Q-learning, with an approximator that incorporates a deep neural network architecture. The security audit itself is modelled as a Markov Decision Process in order to test a number of decisionmaking strategies and compare their convergence to optimality. A series of experimental results is presented to show how this approach can be effectively used to automate penetration testing using a scalable, i.e. not exhaustive, and adaptive approach

Study of off-diagonal disorder using the typical medium dynamical cluster approximation

We generalize the typical medium dynamical cluster approximation (TMDCA) and the local Blackman, Esterling, and Berk (BEB) method for systems with off-diagonal disorder. Using our extended formalism we perform a systematic study of the effects of non-local disorder-induced correlations and of off-diagonal disorder on the density of states and the mobility edge of the Anderson localized states. We apply our method to the three-dimensional Anderson model with configuration dependent hopping and find fast convergence with modest cluster sizes. Our results are in good agreement with the data obtained using exact diagonalization, and the transfer matrix and kernel polynomial methods.Comment: 10 pages, 8 figure

Organisational learning and the organisational life cycle: the differential aspects of an integrated relationship in SMEs

Purpose: This study seeks to relate the practice of organisational learning (OL) in small and medium-sized enterprises (SMEs) to the organisational life cycle (OLC), contextualising the differential aspects of an integrated relationship between them. Design/methodology/approach: It is a mixed method study with two consecutive phases. In Phase I, 30 Hong Kong SMEs identified through theoretical sampling were classified into three life-cycle stages – inception, high-growth, and maturity. In Phase II, their employees’ learning practices (grouped by learning levels) were statistically compared using the Analysis of Variance (ANOVA) and then followed up for confirmation with qualitative semi-structured interviews. Findings: This study uniquely suggests the nature of a relationship between SME organisational learning and the OLC. Empirical results show that three out of the four learning levels (individual, group, organisational, and inter-organisational) practised in SMEs are varied in importance between life-cycle stages. Research limitations/implications: Comparative studies are encouraged in other parts of the world to strengthen the findings – with either SMEs or large organisations. Practical implications: The study informs SME owner/managers about what is important for employee learning at different business stages so that appropriate learning strategies or human resource development (HRD) policies can be formulated in a timely fashion to promote competitiveness. Originality/value: It is among the first studies to connect SME learning with organisational growth. The relationships found serve as a sound foundation for further empirical investigations

A Typical Medium Dynamical Cluster Approximation for the Study of Anderson Localization in Three Dimensions

We develop a systematic typical medium dynamical cluster approximation that provides a proper description of the Anderson localization transition in three dimensions (3D). Our method successfully captures the localization phenomenon both in the low and large disorder regimes, and allows us to study the localization in different momenta cells, which renders the discovery that the Anderson localization transition occurs in a cell-selective fashion. As a function of cluster size, our method systematically recovers the re-entrance behavior of the mobility edge and obtains the correct critical disorder strength for Anderson localization in 3D.Comment: 5 Pages, 4 Figures and Supplementary Material include

Enterprise extension through extensible markup language

An extended enterprise is comprised of multiple linkages between and amongst a company and its suppliers, distributors, customers and others. Linkages are long term collaborative agreements based on synergies and the ability to create value. An extended enterprise eliminates wasteful transaction costs and removes redundancies, delays and inefficiencies from the supply chain. This is accomplished through the coordination of demand forecasting, production planning, deployment and transportation as well as creating organizational and process links with seamless information flows between them. Extended enterprise is enabled by developments in technology, especially information technology. Sharing information about sales forecast, production schedules, inventory, etc. makes an extended enterprise a win/win situation. Extended enterprise networks have used information technology systems such as electronic data interchanges, enterprise resource planning, and the Internet with different degrees of success. The Integrated Manufacturing Technology Initiative has identified several information technology criteria as critical to the success of future enterprises. Based on these criteria, this paper discusses XML’s contribution to the extended enterprise paradigm. Dell’s direct sale model is used to illustrate the role of XML in enterprise extension.Una empresa extendida está compuesta de varios enlaces entre una compañía y sus proveedores, distribuidores, clientes y demás. Estas uniones son acuerdos a largo plazo basados en la sinergia y en la habilidad de crear valor. Una empresa extendida elimina los costes de transacción innecesarios y retira las redundancias, atrasos e ineficiencias de la cadena de suministros. Esto se consigue mediante la coordinación de la demanda, la planificación de la producción, desempleo y transporte así como crear procesos organizativos y enlaces con información que fluye a través de estas partes. Una empresa extendida es posible gracias al Desarrollo en tecnología, especialmente la de la información. Compartir información sobre las ventas, el calendario de producción, el inventario, etc, permite a la empresa situarse en una situación de beneficio. Sus redes de trabajo han empleado la tecnología de la información como intercambios de datos electrónicos, planificación de recursos, y el internet con diferentes grados de éxito. La Iniciativa Artesana de Tecnología Hecha a Mano ha identificado ciertos criterios que resultan críticos para el éxito de las siguientes operaciones y empresas. Basados en estos criterios, este artículo discute la contribución de XML al paradigma de las empresas extendidas. El modelo de ventas directo de Dell se utiliza para ilustrar el papel de XML a la extensión de empresas

Actin filament assembly by bacterial factors VopL/F: Which end is up?

Competing models have been proposed for actin filament nucleation by the bacterial proteins VopL/F. In this issue, Burke et al. (2017. J. Cell Biol. https://doi.org/10.1083/jcb.201608104) use direct observation to demonstrate that VopL/F bind the barbed and pointed ends of actin filaments but only nucleate new filaments from the pointed end

Evolution of pairing from weak to strong coupling on a honeycomb lattice

We study the evolution of the pairing from weak to strong coupling on a honeycomb lattice by Quantum Monte Carlo. We show numerical evidence of the BCS-BEC crossover as the coupling strength increases on a honeycomb lattice with small fermi surface by measuring a wide range of observables: double occupancy, spin susceptibility, local pair correlation, and kinetic energy. Although at low energy, the model sustains Dirac fermions, we do not find significant qualitative difference in the BCS-BEC crossover as compared to those with an extended Fermi surface, except at weak coupling, BCS regime.Comment: 5 page

An empirical study of the effects of unauthorized building works on the property prices of residential buildings in Hong Kong

Thesis (B.Sc)--University of Hong Kong, 2007.Includes bibliographical references (p. 97-101).published_or_final_versio