Unsupervised detection of obfuscated diverse attacks in recommender systems

Hashmi, Saad Sajid 한양대학교 대학원 2015 국내석사

Electronic and Magnetic Properties of 2D Materials: A first principles study

HASHMI ARQUM 부경대학교 대학원 2016 국내박사

In this era, material science progress depends on the discovery of new materials and understand their properties. 2D materials are compounds with reduced dimensionality, which often display unexpected physical and chemical properties. In this thesis, electronic and magnetic properties of 2D materials like graphene, beyond graphene and their hybrid structures will be examined. This thesis will emphasis on Graphene, Graphitic carbon nitride (g-C4N3) and Phosphorene (monolayer of black phosphorus). These three materials has quite different physical, electronic and magnetic properties. For practical device applications, each material is experiencing different problems. In this thesis, we will examine their physical properties as well as try to address the main issues and their solutions by using first principles calculations. Indeed, the free standing graphene shows remarkable electronic, thermal, optical, mechanical and transport properties. However, zero-bandgap limited its advantages to use it in semiconductor industry. This thesis will provide a way to open a bandgap in graphene. Furthermore this thesis also explore the possibility to use graphene for tunneling magnetoresistance (TMR) structure. Thus, Chapter 3 presents the thickness dependent band gap and effective mass of BN/graphene/BN and potential spintronics in Graphene/BN/Co(111) structure. Graphitic carbon nitride (g-C4N3) metal free material showed half metallic properties in the free standing state. For spintronics, it is of interest to examine ferromagnetism in pure 2p electron because of large spin relaxation time is expected owing to the relatively weak spin-orbit coupling. In this thesis, we will to propose physical structural and magnetic properties of the multilayer g-C4N3, hybrid structure and manipulation of electronic and magnetic properties of g-C4N3. Hence, Chapter 4 presents the spin-dependent transport and Optical Properties of Half-Metallic g‐C4N3 Films, Boron nitride (BN) ideal substrate for g‐C4N3 and transition from half metal to semiconductor in doped g-C4N3. Very recently, a new two-dimensional system, so-called phosphorene, was mechanically exfoliated by scotch tape based microcleavage from layered bulk black phosphorus. Phosphorene is a non-magnetic semiconductor with highly anisotropic electrical, mechanical and optical properties. However, the magnetism of phosphorene still remains an open question. In this thesis, we will explore the possibility to find magnetism in phosphorene, as well as phosphorene hybrid structure with graphene. Therefore, Chapter 5 investigates the Transition Metal Doped Phosphorene, magnetic property of porous black phosphorene layer and Graphene/phosphorene bilayer for high electron speed.

Comprehensive Integration of Fisheries Management Policies for Rebuilding Fisheries in South Korea

MD HASHMI SAKIB 부경대학교 대학원 2019 국내석사

The aim of present study is to provide the real scenarios of rebuilding fishery stocks which depleted mainly due to an excess fishing pressure during the last 40 years. Despite the efforts of traditional fisheries management policies against unlawful fishing, unwanted trends were observed with marine fisheries resources. Based on the more than ten years’ experience, FSRP in Korea has proven to be helpful for governing fishery resources for next generations. In 10 years, the fisheries stock rebuilding plan increased revenue earning by 4184.77 million USD. From a social perspective, fisheries enhancement has brought a better livelihood for increasing income in a consistent manner. In South Korea, government agencies implement fisheries policy in accordance with organization’s goals. As a policy, only fisheries stock rebuilding plan (FSRP) or seasonal fishing closure is not enough to recover depleted fish stocks at the desired level. This study evaluated the effectiveness of integrated management in fisheries production. Thus, FSRP and seasonal fishing closure policies were considered for five commercial species i.e. sand fish, blue crab/swimming crab, octopus, skate/ray, and yellow croaker. Again, during FSRP, tokobushi abalone, cod, file fish, Korean flounder and purplish Washington clam were taken from year-round open fishery to make a fruitful summery for designing an effective management plan to restore aquatic resources. Results show that, with FSRP, seasonal closure is really a potential strategy to give strength to vulnerable stocks. Here, blue crab and yellow croaker dominated in production in the seasonally closed fishery, whereas, Korean flounder and cod in the year-round open fishery. Since the beginning of FSRP with seasonal fishing closure, trends in stocks recovery was started to be positive. Even though, stock recovery was found higher within first five years than ten years of FSRP with either seasonal closure or year-round open fishery. Based on CPUE, blue crab showed positive and significant correlation with yellow croaker and skate/ray within the seasonally closed fishery. Whereas, only cod showed a significant negative correlation with tokobushi abalone and purplish Washington clam in the year-round open fishery. This indicates that seasonal fishing closure influenced nicely to rebuild marine stocks in a viable way, however, policy makers also need to revise the existing components of the FSRP policy every five years by doing ecological research concerning marine environment to make a sustainable recovery of marine stock biomass. In addition, fisheries stock rebuilding plans (FSRP) have been moving with some threats of dwelling unavoidable challenges in main policy to achieve rapid effective breakthrough. Therefore, systematic research on the biology of species, mixed catches effects, pollution management and net income loss recovery by stabilizing market for fishermen will be helpful to carryout Korean permanent fisheries rebuilding in the future. At the bottom line, cooperative fisheries resources management by adjacent nations may be a benchmark for rebuilding marine resources not only within EEZ but also between neighboring states.

과학계산 분야를 위한 고성능 저전력의 멀티코어 ARM 클러스터 성능 분석

HASHMI JAHANZEB MAQBOOL 아주대학교 2014 국내석사

No longer the iconic American? The changing cultural and economic value of white masculinity in the global economy

Hashmi, Mobina The University of Wisconsin - Madison 2006 해외박사(DDOD)

This dissertation analyzes the ways in which the economic and cultural value of white masculinity has changed over the last twenty-five years as a result of new technologies of work, globalization, and the transition to a postindustrial information economy. It examines the social, economic, and cultural contexts for the emergence of a new form of citizenship characterized by a splintering of previously unified dimensions of citizenship. This analysis is based on the close study of popular, expert, and policy discourses on automation, outsourcing, and economic productivity in order to map out the shifts in the discursive terrain that have allowed for the displacement of the white male worker from the center of American national identity. By bringing out the connections between the changing meanings of citizenship within the United States and the changing place of the United States in the global economy, this dissertation emphasizes the ways in which globalization has refigured the distribution of power and privilege in a way that affects even hegemonic subject positions. I argue that hierarchies of race and gender, among others, were naturalized by their articulation to a seemingly-egalitarian ideal of productive work that contributed to the well-being of the nation-state. The ideal of productive work was redefined in the 1980s by the increasing use of technology and a technological mindset that re-located productivity in machines, capital, procedures and processes. This led to the construction of laboring humans as a bundle of interchangeable and replaceable human-machine skills, that is as cyborgs. The citizen in contemporary discourse in the United States is one such cyborg subject---hence the idea of a cyborg citizen. These changes meant that the citizen qua (raced, gendered) national subject was much more easily separable from the citizen qua worker, prompting---as seen in nationalist calls for saving "our" jobs from foreign workers---anxieties about the meaning and value of citizenship in this country. It is in this context that I have argued in this dissertation that in a capitalist democracy the cyborg is particularly well-suited to describe the worker-citizen that is the ideal subject of such a system.

Novel architectures for broadband free-space optical communications: Deep-space and terrestrial optical links

Hashmi, Ali Javed Georgia Institute of Technology 2010 해외박사(DDOD)

In this research, the design concept and analysis of different architectures of telescope array-based receivers for an inter-planetary optical communications link between Earth and Mars are presented. Pulse-position modulation (PPM) is used at the transmitter end and photon-counting detectors, along with the direct-detection technique, are employed at each telescope element in the array. First, models for the received signal photons and background noise photons are developed to simulate an optical communications channel between Earth and Mars. A method for optimization of various important system parameters such as detector sizes (i.e., receiver field-of-view), PPM slot-width Ts, and PPM order M, is presented to maximize the communications system performance. Then, the performance of different array architectures is evaluated through analytical techniques and Monte-Carlo simulations for a broad range of deep-space operational scenarios, such as Earth-Mars conjunction, Earth-Mars opposition, and different background and turbulence conditions. It is shown that the performance of array-based receivers consisting of up to 100, 1 m telescopes is almost equivalent to a single large telescope with 10 m aperture diameter. It is also revealed that compared to current radio frequency (RF) technology, telescope array-based optical receivers can provide several orders of magnitude greater data rates from Mars. However, array architectures for deep-space optical communications have several unique challenges. Due to very narrow optical beams, the requirement of spatial tracking of the transmitter line-of-sight at the receiver telescopes (to minimize power losses caused by the tracking errors) is very stern. In addition, detected signals at individual telescope elements in an array need to be synchronized with the receiver clock and with each other before data decoding. Compared to a monolithic large telescope, individual telescope elements in an array receive and detect much less optical power. This phenomenon renders the tracking and synchronization tasks at individual telescopes quite difficult. In the next step, the design of tracking and synchronization subsystems for the array receiver is discussed. The performance of different array architectures, after incorporation of these subsystems, is evaluated for a deep-space optical communications link between Earth and Mars operating in the presence of random tracking and synchronization errors. It is shown that even in the worst-case channel conditions, the designed subsystems successfully perform the tracking and synchronization functions; the impact of synchronization and tracking errors is almost negligible for an array consisting of 100, 1 m telescopes. The tracking and synchronization analysis further solidifies the theoretical foundations and feasibility investigation of telescope arrays for deep-space optical communications. Atmospheric turbulence and diffused background light from the sky during daytime are the major limiting factors in a deep-space optical communications link. This part of the research is focused on developing techniques to mitigate these deleterious effects. Adaptive optics (AO) technology is commonly employed in astronomy to mitigate the turbulence effects. First, laser guide star (LGS)-based AO systems are designed and incorporated in array receivers, and their performance is analyzed for a communications link between Earth and Mars in extreme turbulence and background conditions. It is shown that the incorporation of LGS-based AO systems results in a substantial improvement in the performance of array receivers. Next, a novel space-time adaptive processor (STAP) is developed for post-detection processing and mitigation of background noise effects. The STAP processor can be thought of an electronic counterpart of an active AO system and is very easy and cost-effective to implement. The performance analysis shows that the incorporation of the STAP processor results in several orders of magnitude performance improvement in strong background conditions. The experimental investigation of the use of adaptive optics (AO) subsystems for turbulence and background noise compensation is also carried out. In the last part of the thesis, short-range, terrestrial, free-space optical (FSO) communications links are analyzed. It is believed that FSO systems can solve the last mile connectivity problem faced by the current commercial telecom market. An efficient general-purpose simulation tool is developed that can model and predict the parameters of interest of a laser beam propagating through a turbulent channel in FSO systems. (Abstract shortened by UMI.).