OALib Journal期刊

ISSN: 2333-9721




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匹配条件: “J?K?M?Sadique?Uz?Zaman” ,找到相关结果约669106条。
Review on fifteen Statistical Tests proposed by NIST
Journal of Theoretical Physics and Cryptography , 2012,
Abstract: With a motivation to understand all the fifteen test algorithms and to write their codes independently without looking at various sites mentioned in the NIST document a review study of the NIST Statistical Test Suite is undertaken. All the codes are executed with the test data given in the NIST document and excellent agreements have been found. The codes have been put together in a software, called as CU software, executable in Linux platform. Based on the CU software, exhaustive tests are executed on a long bit sequence generated by the Blum‐Blum‐Shub generator (BBSG). The CU software executes properly giving the results almost matched with those of the NIST results.
A Review Study of NIST Statistical Test Suite: Development of an indigenous Computer Package
J K M Sadique Uz Zaman,Ranjan Ghosh
Computer Science , 2012,
Abstract: A review study of NIST Statistical Test Suite is undertaken with a motivation to understand all its test algorithms and to write their C codes independently without looking at various sites mentioned in the NIST document. All the codes are tested with the test data given in the NIST document and excellent agreements have been found. The codes have been put together in a package executable in MS Windows platform. Based on the package, exhaustive test runs are executed on three PRNGs, e.g. LCG by Park & Miller, LCG by Knuth and BBSG. Our findings support the present belief that BBSG is a better PRNG than the other two.
A simple 1-byte 1-clock RC4 design and its efficient implementation in FPGA coprocessor for secured ethernet communication
Rourab Paul,Sangeet Saha,Jkm Sadique Uz Zaman,Suman Das,Amlan Chakrabarti,Ranjan Ghosh
Computer Science , 2012,
Abstract: In the field of cryptography till date the 1-byte in 1-clock is the best known RC4 hardware design [1], while the 1-byte in 3clocks is the best known implementation [2,3]. The design algorithm in [1] considers two consecutive bytes together and processes them in 2 clocks. The design of 1-byte in 3-clocks is too much modular and clock hungry. In this paper considering the RC4 algorithm, as it is, a simpler RC4 hardware design providing higher throughput is proposed in which 1-byte is processed in 1-clock. In the design two sequential tasks are executed as two independent events during rising and falling edges of the same clock and the swapping is directly executed using a MUX-DEMUX combination. The power consumed in behavioral and structural designs of RC4 are estimated and a power optimization technique is proposed. The NIST statistical test suite is run on RC4 key streams in order to know its randomness property. The encryption and decryption designs are respectively embedded on two FPGA boards with RC4 in a custom coprocessor followed by Ethernet communication.
Developing a Social Business Model for Zero Waste Management Systems: A Case Study Analysis  [PDF]
Atiq Uz Zaman
Journal of Environmental Protection (JEP) , 2012, DOI: 10.4236/jep.2012.311163
Abstract: The global gross domestic product (GDP) has increased by 40% during 1960-2000; poverty and inequity have also increased over the same time [1]. Many social scientists and economists have indicted the existing monetary-based corporate social structures with their insignificant contribution to the problem solving and social development processes. Waste is one of the major problems in every city around the globe. This study explores policy instruments in existing profit maximizing business systems and proposes an alternative business approach for the zero waste management systems. The paper proposes a conceptualized social business model for waste management systems based on a case study of two different organizations working in waste management systems in low and high consuming cities. “Waste Concern”, on one hand, is a social business enterprise, promoting waste recycling activities through the community-based decentralized composting technology using public-private community partnerships model in a low consuming city i.e. Dhaka. “Finding Workable Solutions”, on the other hand, is a non-profit organization that rehabilitates and empowers disabled peoples in high consuming city, i. e. Adelaide by collecting and transforming sellable household waste. This paper argues that waste management social business would be an opportunity for the corporate world to implement the strategy of extended producer responsibility in more successful way. Under this business model, producers can contribute more significantly in the social development process, promote value creation, ensure product stewardship and equity within the society. In addition, the conceptualized waste management social business model will endorse closed-loop resource flow in the society and will maximize resource utilization through recycling, reusing and re-gifting in the circular society.
Sustainable Approach to Regenerating Residential Form and Density: Case in Dhaka
Quazi M. Mahtab-Uz Zaman,Richard Laing
Urban Studies Research , 2013, DOI: 10.1155/2013/783792
Abstract: This paper presents principles and praxis of sustainable approach to maintaining targeted “residential regeneration by density” yet achieving innovations in urban form in a contextual scenario of Dhaka City, the capital of Bangladesh. It is evident from the context that Dhaka is experiencing a dramatic transformation in residential density due to demographic changes during the past two decades due the concentration of social, administrative, institutional, recreational, small-scale industries, and associated housing facilities. The transformation is visible in residential built footprint, significantly due to the demand-driven and density-led market, originated from low rise and low density and transforming to high density high rise. This transformation has been consistently threatening social and environmental realm indicated by depletion of garden houses; reduction of public parks; shrinking walkways; deletion of setback for ventilation and sun shade from trees; slowing down mobility; and obstruction of physical and visual permeability. The paper discussed a pragmatic approach that professionals have adopted to control the density and to introduce scopes for innovative urban forms by way of applying floor area ratio (FAR) methods and further discusses the merits of the methodological process of exercising morphology with a set of new building rules without undermining the market demand. 1. Strength of Urban Form and Density in Regeneration Regeneration occurs in varying forms and depends on the level of urban deterioration; frequency of changing functions and land uses; speculative real estate market; and socioeconomic transformation affected by globalization [1]. Regeneration in Dhaka city adopted the method of “transformation by densification” in response to the competitive real estate market; globalization; rising affluent societies; rapid demographic shift; and deterioration of built forms, while Dhaka has shaped as one of the popular destinations for major socioeconomic and administrative development. This triggers pulling effects of population from the peripheral cities and other districts for job; education; health and judicial services; administrative support; and for major urban realm [2, 3]; all these have been pushing Dhaka’s growth limit to the north (Figure 1). Figure 1: Urbanization in 380 years Dhaka [ 10]. Dhaka city’s concentration is a one way demographic shift since reciprocal distribution of population to other districts rarely happens mostly due to other locale being weakly connected by infrastructure and being less attractive for
Tuning the structural and dynamical properties of a dipolar Bose-Einstein condensate: Ripples and instability islands
M. Asad-uz-Zaman,D. Blume
Physics , 2009, DOI: 10.1088/1367-2630/12/6/065022
Abstract: It is now well established that the stability of aligned dipolar Bose gases can be tuned by varying the aspect ratio of the external harmonic confinement. This paper extends this idea and demonstrates that a Gaussian barrier along the strong confinement direction can be employed to tune both the structural properties and the dynamical stability of an oblate dipolar Bose gas aligned along the strong confinement direction. In particular, our theoretical mean-field analysis predicts the existence of instability islands immersed in otherwise stable regions of the phase diagram. Dynamical studies indicate that these instability islands, which can be probed experimentally with present-day technology, are associated with the going soft of a Bogoliubov--de Gennes excitation frequency with radial breathing mode character. Furthermore, we find dynamically stable ground state densities with ripple-like oscillations along the radial direction. These structured ground states exist in the vicinity of a dynamical radial roton-like instability.
Aligned dipolar Bose-Einstein condensate in a double-well potential: From cigar-shaped to pancake-shaped
M. Asad-uz-Zaman,D. Blume
Physics , 2009, DOI: 10.1103/PhysRevA.80.053622
Abstract: We consider a Bose-Einstein condensate (BEC), which is characterized by long-range and anisotropic dipole-dipole interactions and vanishing s-wave scattering length, in a double-well potential. The properties of this system are investigated as functions of the height of the barrier that splits the harmonic trap into two halves, the number of particles (or dipole-dipole strength) and the aspect ratio $\lambda$, which is defined as the ratio between the axial and longitudinal trapping frequencies $\omega_z$ and $\omega_{\rho}$. The phase diagram is determined by analyzing the stationary mean-field solutions. Three distinct regions are found: a region where the energetically lowest lying stationary solution is symmetric, a region where the energetically lowest lying stationary solution is located asymmetrically in one of the wells, and a region where the system is mechanically unstable. For sufficiently large aspect ratio $\lambda$ and sufficiently high barrier height, the system consists of two connected quasi-two-dimensional sheets with density profiles whose maxima are located either at $\rho=0$ or away from $\rho=0$. The stability of the stationary solutions is investigated by analyzing the Bogoliubov de Gennes excitation spectrum and the dynamical response to small perturbations. These studies reveal unique oscillation frequencies and distinct collapse mechanisms. The results derived within the mean-field framework are complemented by an analysis based on a two-mode model.
Directional flow of solitons with asymmetric potential wells: Soliton diode
M. Asad-uz-zaman,U. Al Khawaja
Physics , 2013, DOI: 10.1209/0295-5075/101/50008
Abstract: We study the flow of bright solitons through two asymmetric potential wells. The scattering of a soliton by certain type of single potential wells, e.g., Gaussian or Rosen-Morse, is distinguished by a critical velocity above which solitons can transmit almost completely and below which solitons can reflect nearly perfectly. For two such wells in series with certain parameter combinations, we find that there is an appreciable velocity range for which solitons can propagate in one direction only. Our study shows that this directional propagation or diode behavior is due to a combined effect of the sharp transition in the transport coefficients at the critical velocity and a slight reduction in the center-of-mass speed of the soliton while it travels across a potential well.
Modification of roton instability due to the presence of a second dipolar Bose-Einstein condensate
M. Asad-uz-Zaman,D. Blume
Physics , 2011, DOI: 10.1103/PhysRevA.83.033616
Abstract: We study the behavior of two coupled purely dipolar Bose-Einstein condensates, each located in a cylindrically symmetric pancake-shaped external confining potential, as the separation b between the traps along the tight confining direction is varied. The solutions of the coupled Gross-Pitaevskii and Bogoliubov-de Gennes equations, which account for the full dynamics, show that the system behavior is modified by the presence of the second dipolar BEC. For sufficiently small b, the presence of the second dipolar BEC destabilizes the system dramatically. In this regime, the coupled system collapses through a mode that is notably different from the radial roton mode that induces the collapse of the uncoupled system. Finally, we comment on the shortcomings of an approach that neglects the dynamics in the z-direction, which is assumed to be a good approximation for highly pancake-shaped dipolar BECs in the literature.
Influenza in Outpatient ILI Case-Patients in National Hospital-Based Surveillance, Bangladesh, 2007–2008
Rashid Uz Zaman,A. S. M. Alamgir,Mustafizur Rahman,Eduardo Azziz-Baumgartner,Emily S. Gurley,M. Abu Yushuf Sharker,W. Abdullah Brooks,Tasnim Azim,Alicia M. Fry,Stephen Lindstrom,Larisa V. Gubareva,Xiyan Xu,Rebecca J. Garten,M. Jahangir Hossain,Salah Uddin Khan,Labib Imran Faruque,Syeda Shegufta Ameer,Alexander I. Klimov,Mahmudur Rahman,Stephen P. Luby
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0008452
Abstract: Recent population-based estimates in a Dhaka low-income community suggest that influenza was prevalent among children. To explore the epidemiology and seasonality of influenza throughout the country and among all age groups, we established nationally representative hospital-based surveillance necessary to guide influenza prevention and control efforts.

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