Atif Khan - Academia.edu (original) (raw)

Papers by Atif Khan

Research paper thumbnail of Cryptography, security and privacy (CrySP) research group

XRDS: Crossroads, The ACM Magazine for Students, 2013

Research paper thumbnail of Privacy-Centric Access Control for Distributed Heterogeneous Medical Information Systems

2013 IEEE International Conference on Healthcare Informatics, 2013

Research paper thumbnail of Principal Component and Factor Analysis to Study Variations in the Aging Lumbar Spine

IEEE Journal of Biomedical and Health Informatics, 2014

Human spine is a multifunctional structure of human body consisting of bones, joints, ligaments a... more Human spine is a multifunctional structure of human body consisting of bones, joints, ligaments and muscles which all undergo a process of change with the age. A sudden change in these features either naturally or thorough injury can lead to some serious medical conditions which puts huge burden on health services and economy. While aging is inevitable, the effect of aging on different areas of spine is of clinical significance. This paper reports the growth and degenerative pattern of human spine using principal component analysis. Some noticeable lumbar spine features such as vertebral heights, disc heights, disc signal intensities, para-spinal muscles, subcutaneous fats, psoas muscles and cerebrospinal fluid were used to study the variations seen on lumbar spine with the natural aging. These features were extracted from lumbar spine magnetic resonance images of 61 subjects with age ranging from 2 to 93 years. Principal component analysis is used to transform complex and multivariate feature space to a smaller meaningful representation. PCA transformation provided 2D visualization and knowledge of variations among spinal features. Further useful information about correlation among the spinal features is acquired through factor analysis. The knowledge of age related changes in spinal features are important in understanding different spine related problems.

Research paper thumbnail of Conversion Disorder; an unusual etiology of wrist drop: Report of a case and review of literature

Balkan Military Medical Review, 2014

Wrist drop is commonly a consequence of Radial Nerve injury and infrequently due to C7/C8 radicul... more Wrist drop is commonly a consequence of Radial Nerve injury and infrequently due to C7/C8 radiculopathy, brachial plexus lesion or central causes. We present here a rare case of wrist drop due to conversion disorder. He was a 31-year-old soldier who presented with left sided wrist drop and numbness over dorsal aspect of left hand following gunshot injury to the left forearm. His repeated electrophysiological evaluation revealed injury to the sensory branch of left Radial Nerve. Magnetic resonance imaging of brain, muscle enzymes and routine laboratory investigations were normal. After getting treatment as a case of radial nerve injury, focal dystonia and adjustment disorder he was finally diagnosed as a case of conversion disorder. Motor point blocks, orthotic support, electrical muscle stimulation, cognitive behavioral therapy and biofeedback were tried but did not prove effective. Patient ultimately landed up with the psychiatrist and is still under his treatment. Conversion disorder may be considered in a patient presenting with wrist drop when no organic cause can be found. Early opinion of a psychiatrist is needed to be sought in suspicious cases after providing relevant clinical findings and investigations.

Research paper thumbnail of Effects of power system parameters on critical clearing time: comprehensive analysis

Electric Power Systems Research, 1999

In this paper, the effects of various power system parameters on the critical clearing time are p... more In this paper, the effects of various power system parameters on the critical clearing time are presented. The various parameters for which the analysis is presented include the machine parameters, i.e. damping, inertia constant and transient reactance, and system parameters, i.e. line impedance, transformer impedance and fault impedance. Various configurations of faults are also investigated. The simplest single machine infinite bus power system was simulated. Plots and relationships for each parameter are presented and conclusions are drawn from their behavior. The paper is a comprehensive treatment of the time domain method to the single machine system and is particularly helpful to the utility power engineers and researchers in the electric machines area to comprehend the system behavior for various system parameters. The results can be generalized to the large scale multimachine power systems as well.

Research paper thumbnail of Electrical energy conservation and its application to a sheet glass industry

IEEE Spectrum, 1996

... Atif Zaman Khan ... From our study of cogeneration [ 11, such a high temperature is enough to... more ... Atif Zaman Khan ... From our study of cogeneration [ 11, such a high temperature is enough to generate 400 MW of electricity As an illustration, Table 6 gives the overall energy savings for a cogeneration scheme to produce a 100 Mwh of electrical ... The author wishes to thank Prof. ...

Research paper thumbnail of A PC based software package for the equal area criterion of power system transient stability

IEEE Transactions on Power Systems, 1998

Page 1. IEEE Transactions on Power Systems, Vol. 13, No. 1, February 1998 A PC BASED SOFI&amp... more Page 1. IEEE Transactions on Power Systems, Vol. 13, No. 1, February 1998 A PC BASED SOFI'WARE PACKAGE FOR THE EQUAL AREA CRITERION OF POWER SYSTEM TRANSIENT STABILITY 21 Atif Zaman Khan Member ...

Research paper thumbnail of A discussion and analysis of the voltage stability problems in Oman

Electric Power Systems Research, 1999

In this paper, the problems encountered in system voltages for a fast growing utility, i.e. the M... more In this paper, the problems encountered in system voltages for a fast growing utility, i.e. the Ministry of Electricity and Water of the Sultanate of Oman in the Arabian Gulf are discussed. The utility has mostly air-conditioning load in the summer and the system encountered voltage stability problems during peak summer conditions. The paper presents a detailed discussion on recommendations proposed to remedy the voltage problems. The most critical period for voltage problems during summer days and its effect on remote load buses in terms of voltage profile is discussed. System wide weak voltage buses have been identified.

Research paper thumbnail of Effects of power system parameters on critical clearing time: comprehensive analysis

Electric Power Systems Research, 1999

In this paper, the effects of various power system parameters on the critical clearing time are p... more In this paper, the effects of various power system parameters on the critical clearing time are presented. The various parameters for which the analysis is presented include the machine parameters, i.e. damping, inertia constant and transient reactance, and system parameters, i.e. line impedance, transformer impedance and fault impedance. Various configurations of faults are also investigated. The simplest single machine infinite bus power system was simulated. Plots and relationships for each parameter are presented and conclusions are drawn from their behavior. The paper is a comprehensive treatment of the time domain method to the single machine system and is particularly helpful to the utility power engineers and researchers in the electric machines area to comprehend the system behavior for various system parameters. The results can be generalized to the large scale multimachine power systems as well.

Research paper thumbnail of SINGLE MACHINE INFINITE BUS POWER SYSTEM TRANSIENT STABILITY: SOFTWARE IMPLEMENTATION

Electric Machines & Power Systems, 1998

Page 1. SINGLE MACHINE INFINITE BUS POWER SYSTEM TRANSIENT STABILITY: SOFTWARE IMPLEMENTATION ATI... more Page 1. SINGLE MACHINE INFINITE BUS POWER SYSTEM TRANSIENT STABILITY: SOFTWARE IMPLEMENTATION ATIF ZAMAN KHAN Department of Electrical & Electronics Engineering Sultan Qaboos University Muscat, Sultanate of OMAN ...

Research paper thumbnail of Student training in the undergraduate curriculum of power system transient stability

Computers & Electrical Engineering, 1998

This paper describes a set of power system laboratory exercises assigned for student training in ... more This paper describes a set of power system laboratory exercises assigned for student training in the undergraduate curriculum of power system transient stability to senior students at two universities. These exercises utilize a user-friendly, interactive PC-based graphical software package for the comprehension of power system transient stability. The exercises cover the classical method of equal area criterion for the single machine in®nite bus system and help the students to acquire a realistic feeling of the transient stability problem with an on-line explanation of the various eects of faults on transient stability. The exercise description, student reaction and the utilization of the software are discussed. #

Research paper thumbnail of Cryptography, security and privacy (CrySP) research group

XRDS: Crossroads, The ACM Magazine for Students, 2013

Research paper thumbnail of Privacy-Centric Access Control for Distributed Heterogeneous Medical Information Systems

2013 IEEE International Conference on Healthcare Informatics, 2013

Research paper thumbnail of Principal Component and Factor Analysis to Study Variations in the Aging Lumbar Spine

IEEE Journal of Biomedical and Health Informatics, 2014

Human spine is a multifunctional structure of human body consisting of bones, joints, ligaments a... more Human spine is a multifunctional structure of human body consisting of bones, joints, ligaments and muscles which all undergo a process of change with the age. A sudden change in these features either naturally or thorough injury can lead to some serious medical conditions which puts huge burden on health services and economy. While aging is inevitable, the effect of aging on different areas of spine is of clinical significance. This paper reports the growth and degenerative pattern of human spine using principal component analysis. Some noticeable lumbar spine features such as vertebral heights, disc heights, disc signal intensities, para-spinal muscles, subcutaneous fats, psoas muscles and cerebrospinal fluid were used to study the variations seen on lumbar spine with the natural aging. These features were extracted from lumbar spine magnetic resonance images of 61 subjects with age ranging from 2 to 93 years. Principal component analysis is used to transform complex and multivariate feature space to a smaller meaningful representation. PCA transformation provided 2D visualization and knowledge of variations among spinal features. Further useful information about correlation among the spinal features is acquired through factor analysis. The knowledge of age related changes in spinal features are important in understanding different spine related problems.

Research paper thumbnail of Conversion Disorder; an unusual etiology of wrist drop: Report of a case and review of literature

Balkan Military Medical Review, 2014

Wrist drop is commonly a consequence of Radial Nerve injury and infrequently due to C7/C8 radicul... more Wrist drop is commonly a consequence of Radial Nerve injury and infrequently due to C7/C8 radiculopathy, brachial plexus lesion or central causes. We present here a rare case of wrist drop due to conversion disorder. He was a 31-year-old soldier who presented with left sided wrist drop and numbness over dorsal aspect of left hand following gunshot injury to the left forearm. His repeated electrophysiological evaluation revealed injury to the sensory branch of left Radial Nerve. Magnetic resonance imaging of brain, muscle enzymes and routine laboratory investigations were normal. After getting treatment as a case of radial nerve injury, focal dystonia and adjustment disorder he was finally diagnosed as a case of conversion disorder. Motor point blocks, orthotic support, electrical muscle stimulation, cognitive behavioral therapy and biofeedback were tried but did not prove effective. Patient ultimately landed up with the psychiatrist and is still under his treatment. Conversion disorder may be considered in a patient presenting with wrist drop when no organic cause can be found. Early opinion of a psychiatrist is needed to be sought in suspicious cases after providing relevant clinical findings and investigations.

Research paper thumbnail of Effects of power system parameters on critical clearing time: comprehensive analysis

Electric Power Systems Research, 1999

In this paper, the effects of various power system parameters on the critical clearing time are p... more In this paper, the effects of various power system parameters on the critical clearing time are presented. The various parameters for which the analysis is presented include the machine parameters, i.e. damping, inertia constant and transient reactance, and system parameters, i.e. line impedance, transformer impedance and fault impedance. Various configurations of faults are also investigated. The simplest single machine infinite bus power system was simulated. Plots and relationships for each parameter are presented and conclusions are drawn from their behavior. The paper is a comprehensive treatment of the time domain method to the single machine system and is particularly helpful to the utility power engineers and researchers in the electric machines area to comprehend the system behavior for various system parameters. The results can be generalized to the large scale multimachine power systems as well.

Research paper thumbnail of Electrical energy conservation and its application to a sheet glass industry

IEEE Spectrum, 1996

... Atif Zaman Khan ... From our study of cogeneration [ 11, such a high temperature is enough to... more ... Atif Zaman Khan ... From our study of cogeneration [ 11, such a high temperature is enough to generate 400 MW of electricity As an illustration, Table 6 gives the overall energy savings for a cogeneration scheme to produce a 100 Mwh of electrical ... The author wishes to thank Prof. ...

Research paper thumbnail of A PC based software package for the equal area criterion of power system transient stability

IEEE Transactions on Power Systems, 1998

Page 1. IEEE Transactions on Power Systems, Vol. 13, No. 1, February 1998 A PC BASED SOFI&amp... more Page 1. IEEE Transactions on Power Systems, Vol. 13, No. 1, February 1998 A PC BASED SOFI'WARE PACKAGE FOR THE EQUAL AREA CRITERION OF POWER SYSTEM TRANSIENT STABILITY 21 Atif Zaman Khan Member ...

Research paper thumbnail of A discussion and analysis of the voltage stability problems in Oman

Electric Power Systems Research, 1999

In this paper, the problems encountered in system voltages for a fast growing utility, i.e. the M... more In this paper, the problems encountered in system voltages for a fast growing utility, i.e. the Ministry of Electricity and Water of the Sultanate of Oman in the Arabian Gulf are discussed. The utility has mostly air-conditioning load in the summer and the system encountered voltage stability problems during peak summer conditions. The paper presents a detailed discussion on recommendations proposed to remedy the voltage problems. The most critical period for voltage problems during summer days and its effect on remote load buses in terms of voltage profile is discussed. System wide weak voltage buses have been identified.

Research paper thumbnail of Effects of power system parameters on critical clearing time: comprehensive analysis

Electric Power Systems Research, 1999

In this paper, the effects of various power system parameters on the critical clearing time are p... more In this paper, the effects of various power system parameters on the critical clearing time are presented. The various parameters for which the analysis is presented include the machine parameters, i.e. damping, inertia constant and transient reactance, and system parameters, i.e. line impedance, transformer impedance and fault impedance. Various configurations of faults are also investigated. The simplest single machine infinite bus power system was simulated. Plots and relationships for each parameter are presented and conclusions are drawn from their behavior. The paper is a comprehensive treatment of the time domain method to the single machine system and is particularly helpful to the utility power engineers and researchers in the electric machines area to comprehend the system behavior for various system parameters. The results can be generalized to the large scale multimachine power systems as well.

Research paper thumbnail of SINGLE MACHINE INFINITE BUS POWER SYSTEM TRANSIENT STABILITY: SOFTWARE IMPLEMENTATION

Electric Machines & Power Systems, 1998

Page 1. SINGLE MACHINE INFINITE BUS POWER SYSTEM TRANSIENT STABILITY: SOFTWARE IMPLEMENTATION ATI... more Page 1. SINGLE MACHINE INFINITE BUS POWER SYSTEM TRANSIENT STABILITY: SOFTWARE IMPLEMENTATION ATIF ZAMAN KHAN Department of Electrical & Electronics Engineering Sultan Qaboos University Muscat, Sultanate of OMAN ...

Research paper thumbnail of Student training in the undergraduate curriculum of power system transient stability

Computers & Electrical Engineering, 1998

This paper describes a set of power system laboratory exercises assigned for student training in ... more This paper describes a set of power system laboratory exercises assigned for student training in the undergraduate curriculum of power system transient stability to senior students at two universities. These exercises utilize a user-friendly, interactive PC-based graphical software package for the comprehension of power system transient stability. The exercises cover the classical method of equal area criterion for the single machine in®nite bus system and help the students to acquire a realistic feeling of the transient stability problem with an on-line explanation of the various eects of faults on transient stability. The exercise description, student reaction and the utilization of the software are discussed. #