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Muhammad Omer Khan,Saeed Zaman,Muhammad Mehdi,Chul-Ho Noh,Gi-Hyeon Gwon,Chul-Hwan Kim 한국조명·전기설비학회 2017 조명·전기설비학회논문지 Vol.31 No.10
Conventional AC power networks in recent decades have been in a process of continuous overhaul due to the development of power electronic devices and distributed energy resources (DER). This development has demonstrated great potential for the implementation of DC power networks and numerous effects on the employment of integrated AC/DC systems based on Voltage Source Converter (VSC) technology are underway. On the other hand, the integration of DER in a distribution network has emerged as a durable choice for fulfilling future energy need. In this study, a load flow analysis is performed on a Voltage Source Converter-Multi terminal DC (VSC-MTDC) based AC/DC Distribution system incorporated with DERs. An IEEE 14 bus distribution network was modified to include a VSC-MTDC network model for the implementation of the Newton-Raphson load flow algorithm. This paper also discussed the mathematical models for VSC, AC and DC networks along with the load flow study of the steady-state change in the AC/DC network as a result of converter and DC line outage.
Frequency Profile Improvement of a Microgrid under Abnormal Conditions via a Demand Response Program
Muhammad Saeed uz Zaman,Raza Haider,Syed Basit Ali Bukhari,Yun-Sik Oh,Min-Sung Kim,Muhammad Mehdi,Chul-Hwan Kim 한국조명·전기설비학회 2017 조명·전기설비학회논문지 Vol.31 No.10
The frequency deviation of an electric power system from its nominal range is a significant indicator of the system’s instability. This issue is further highlighted when the system is incorporated with intermittent renewable energy resources. In this work, the frequency regulation of a microgrid is achieved by a demand response program. The proposed plan is implemented in a central controller that has two control sections. The frequency deviation is controlled by manipulating responsive loads. In the case of higher frequency deviation, the command of the first control section is proportional to the magnitude of frequency deviation and a large amount of responsive loads is manipulated to restore the frequency to its nominal range quickly. The other section of the central controller addresses minor frequency deviations. The proposed plan is implemented on a test system and outperforms the conventional methods in terms of frequency restoration. The improvement in voltage profile is also observed during abnormal conditions after the proposed plan is implemented.
Effect of heat treatment on impact resistance of AU5GT and AS7G06 aluminum alloys
Muhammad Muzamil,Maaz Akhtar,Muhammad Samiuddin,Murtuza Mehdi 대한기계학회 2016 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.30 No.10
Impact strength is one of the major mechanical properties that a material should possess in order to absorb sudden changes in the load intensity. The objective of current study is to compare the impact strength of two material (AU5GT and AS7G06), which are used in different structural applications. Almost no work is available which compares the impact strength of selected grade alloys along with different heat treatment cycles. Specimens are heat treated first as per designed cycles, later impact testing is performed. Charpy impact test is conducted in accordance with ASTM E23-12 standard method on three samples with and without heat treatment for each cycle. Solutionizing on samples is done at constant time and temperature to achieve homogenization. Later, aging is conducted at different temperatures ranging from 100-200°C (different intervals) at constant time to find the effect of precipitation hardness that actually increases the strength. Sample hardness is determined using Vickers micro hardness testing machine for each heat treatment cycle. Charpy test results provided the impact energy that is used to determine the strength before fracture. Heat treated samples have showed increase in impact strength for AS7G06 aluminum alloy while AU5GT shows very little change. This is because of growing the precipitation with respect to temperature, which resulted in more hard regions across grains. Hardness also shows an increasing relationship, as expected. Fracture surfaces are analyzed on stereo microscopy and Scanning electron microscopy (SEM) to find the final mode of fracture, that is brittle, ductile or transitional (combination of both brittle and ductile).
Intelligent Agent Based Architectures for E-Learning System : Survey
Muhammad Arif,Mehdi Hussain 보안공학연구지원센터 2015 International Journal of u- and e- Service, Scienc Vol.8 No.6
E-learning is the internet enabled learning. Internet has ongoing to restructuring education. Intelligent agent based e-learning provide a common infrastructure to assimilate varied software components. There are two sorts of e-learning synchronous and asynchronous. This paper described the detail of well-known agent based architecture for e-learning. E-learning is going to be gigantic. There are multiple benefits of e-learning; it is convenient, self-service mix, match, on demand any time anyplace, private learning, Self-paced and elastic. E-learning provide cost effective and virtual environment. E-learning gives the ability to user to collect the quantifiable and sensible material, examine, and distribute and custom e-learning knowledge from multiple e learning sources.
Muhammad Arif,Asad Khatak,Mehdi Hussain 보안공학연구지원센터 2015 International Journal of Bio-Science and Bio-Techn Vol.7 No.3
Now-a-days, in Pakistan especially in strategic, military and private sector hospitals, there is an increasing use of hospital information systems. It has been seemed that a localize approach for developing HMIS is prevailing i.e. conventional use of relational database system, which are isolated from others hospitals or remote data collection centers. In this, paper a framework is proposed for establishment of data warehouse to centralize data from remote hospitals and collection centers. Data mining and knowledge discovery modal is also discussed.
Mehdi Hussain,Ainuddin Wahid Abdul Wahab,Ishrat Batool,Muhammad Arif 보안공학연구지원센터 2015 International Journal of Security and Its Applicat Vol.9 No.2
The significance of digital information security has been enhanced due to the boost of internet communication. Providing security for server client communication over the internet is a critical issue due to open world digital eavesdroppers. Generally, password authentication is required for establishing a connection between server and client environment. The client password is verified by the server ends to establish a valid connection. Successful password verification initiates the client and server to perform further secured request and response mechanisms. The problem of password authentication over insecure networks presents in many application areas, such as web login, remote logins of computer networks. Hence the significance of confidential password transmission over insecure internet becomes the necessity of secure authentication. In this paper, we proposed a secure password transmission over the internet for authentication of server/client environment using encryption and image steganography. Client password is first encrypted and embedded in an image using steganographic algorithm at client side and transmitted over unsecured network to the web server. On the other side server extract safely password from image steganography decoding algorithm, decrypt and verified it’s with SQL database server. In case if the intruder steals the image over network he/she will be unable to decode the password from the image. The prototype of the proposed method is implemented using JavaScript, Html, and ASP.net for verification purpose.
Infantile Colic: A Survey of Physicians in Pakistan
Muhammad Saif Jalal,Syed Zafar Mehdi,Jalal Uddin Akber,Murtaza Ali Gowa,Carlos Lifschitz 대한소아소화기영양학회 2024 Pediatric gastroenterology, hepatology & nutrition Vol.27 No.3
Purpose: Infantile colic diagnostic criteria were established by Rome IV. A universally accepted management remains to be established. We aimed to evaluate diagnostic criteria, management strategies, and perceived regional prevalence of infantile colic in Pakistan, as well as its effect on physicians and parents. Methods: A questionnaire was distributed amongst 1,256 physicians. Results: We received 800 replies. Wessel and Rome IV criteria were used by most physicians for diagnosis; however, the response “any infant who cries a lot” was selected by older physicians (48% of those over 60 years), physicians in rural areas (32%), physicians practicing in private clinics (27%), and general physicians (30%). Estimated prevalence of infantile colic ranges from 21–40%. Reassurance was the most widely recommended management strategy followed by herbal teas (51%), switching to a different formula (49%), probiotics (28%) and antibiotics (26%), discontinuation of breastfeeding (14%), elimination of dairy products from the breastfeeding mothers’ diet (6%), and the administration of colic drops (1%). Most physicians considered the negative impact of colic on their personal lives and the parents as mild-to-moderate. Notably, 38% of percent of physicians routinely screened for maternal depression, and 45% of physicians were aware of the association between infantile colic and shaken baby syndrome. Conclusion: Most physicians in Pakistan diagnose and manage infantile colic according to the established guidelines. However, the guidelines pertaining to treatment planning are not followed. Educational efforts directed toward general physicians and doctors practicing in rural areas and clinics must be implemented to avoid unnecessary testing and treatment burden.