oalib

Publish in OALib Journal

ISSN: 2333-9721

APC: Only $99

Submit

Any time

2019 ( 41 )

2018 ( 270 )

2017 ( 277 )

2016 ( 273 )

Custom range...

Search Results: 1 - 10 of 149544 matches for " H. Alidu "
All listed articles are free for downloading (OA Articles)
Page 1 /149544
Display every page Item
IEC 61850 SCL Validation Using UML Model in Modern Digital Substation  [PDF]
Byungtae Jang, Alidu Abubakari, Namdae Kim
Smart Grid and Renewable Energy (SGRE) , 2018, DOI: 10.4236/sgre.2018.98009
Abstract: The IEC 61850 standard stipulates the Substation Configuration Description Language (SCL) file as a means to define the substation equipment, IED function and also the communication mechanism for the substation area network. The SCL is an eXtensible Markup Language (XML) based file which helps to describe the configuration of the substation Intelligent Electronic Devices (IED) including their associated functions. The SCL file is also configured to contain all IED capabilities including data model which is structured into objects for easy descriptive modeling. The effective functioning of this SCL file relies on appropriate validation techniques which check the data model for errors due to non-conformity to the IEC 61850 standard. In this research, we extend the conventional SCL validation algorithm to develop a more advanced validator which can validate the standard data model using the Unified Modeling Language (UML). By using the Rule-based SCL validation tool, we implement validation test cases for a more comprehensive understanding of the various validation functionalities. It can be observed from the algorithm and the various implemented test cases that the proposed validation tool can improve SCL information validation and also help automation engineers to comprehend the IEC 61850 substation system architecture.
A Study on Unified Testing Method for IEC 61850 Based Server with Focus on Setting Group Function  [PDF]
Namdae Kim, Alidu Abubakari, Byungtae Jang
Smart Grid and Renewable Energy (SGRE) , 2018, DOI: 10.4236/sgre.2018.910012
Abstract: The digital substation system consists of an Intelligent Electronic Device (IED) which requires information for the supervision, protection, and control, as well as a client operating system for substation operation. IEC 61850 communication standard has been defined for information exchange between heterogeneous digital devices in such substations. Currently, the Korea Electric Power Corporation (KEPCO) digital substation system uses unbuffered reporting and Generic Object Oriented Substation Events (GOOSE) communication functions for monitoring, protection and control automation. However, it is expected that the Setting Group function will be needed to operate adaptive intelligent substation system. The Setting Group function is advantageous in that it is possible to change the setting of the IED in one unified way through the client operating system, rather than changing the correction value of an IED through different manufacturer-based engineering tools. In order to utilize the Setting Group function of the IED in real substation scenario, it is necessary to test both the communication function with the host operating device and the electric functional test to ensure that correction value is properly changed. In this paper, we introduce the IEC 61850 Setting Group function, and propose a method that can integrate communication function and electrical function test of an IED conforming to the setting group functionality. We also tested the Setting Group function of the actual IED device through the proposed integrated functional test method and analyzed the results. We were able to simplify the process of testing both the electrical and communication signals in digital substations.
Development of a Model Driven ACSI Conformance Testing for IEC 61850-Based IED  [PDF]
Byungtae Jang, Alidu Abubakari, Namdae Kim
Smart Grid and Renewable Energy (SGRE) , 2018, DOI: 10.4236/sgre.2018.910014
Abstract: Globally, traditional power systems are rapidly transforming towards the adoption of smart grid platforms. Substations which are at the center of the electric power transformation from the power plant are changing to IEC 61850 based digital substations. Therefore, within substation, there is a growing demand for the IEC 61850 based Intelligent Electronic Devices (IEDs). The operation of multiple manufacturers of IEDs in a single digital substation network increases the need for IEC 61850 communications specification conformance diagnosis to ensure interoperability for efficient data exchange between IEDs. The IEC 61850-10 presents test items for diagnosing communication specification conformance. There are many test tools available in the market today to test the compliance of the IEC 61850 communications specifications to the IED. In this paper, we propose a model-based diagnostic method for IED communication conformance testing. The proposed model-based software therefore uses the “drag and drop” technique to select the various IEC 61850 communication services (objects) required to design the test case in a user friendly Graphical User Interface (GUI). This makes the service conformance testing more flexible for test engineers and system integrators especially in situations that require test case modifications. Also, the proposed software tool makes it easy to understand the various IEC 61850 services using the friendly GUI.
Testosterone and Its Bioactive Components Are Associated with Libido and the Metabolic Syndrome in Men  [PDF]
H. Alidu, N. Amidu, W. K. B. A. Owiredu, C. K. Gyasi-Sarpong, A. T. Bawah, P. P. M. Dapare, E. B. Agyemang Prempeh
Advances in Sexual Medicine (ASM) , 2017, DOI: 10.4236/asm.2017.72008
Abstract: Background: Some evidence has shown that the prevalence of hypoactive sexual desire and erectile dysfunction (ED) is associated with testosterone levels whilst higher levels of testosterone have been reported to increase the frequency of intercourse. Available evidence points towards an etiologic role for hypogonadism in the causation of diabetes, metabolic syndrome (Mets) and sexual dysfunction (SD) even though the exact pathophysiological linkage is yet to be fully elucidated. This study therefore sought to evaluate the impact of testosterone as well as its bioactive components on both the MetS and SD. Method: Diabetic men engaged in a stable heterosexual relationship for at least 2 years were recruited for this study. Participants were at least 18 years and provided an informed and signed consent to partake in this study. Fasting blood samples were taken from the participants for biochemical and hormonal assay. The participants were then evaluated using the Golombok Rust Inventory of Sexual Satisfaction for males (GRISS-M). Metabolic syndrome was assessed using the NCEP-ATP III, IDF and WHO criteria. All data analyses were performed using the SPSS software, version 11.0 systat, Inc. Germany and GraphPad Prism, version 5.0, San Diego California, USA. Results: The mean total, free and bioavailable testosterone as well as SHBG recorded among the participants was 7.10 ± 1.23 ng/ml, 0.10 ± 0.01 ng/ml, 7.01 ± 1.41 ng/ml and 4.33 ± 1.12 nmol/l respectively. Subjects with the MetS showed significantly lower SHBG levels in comparison with subjects without the MetS. Participants with raised triglyceride levels showed significantly lower levels of total, free and bioavailable testosterone when compared to participant without raised triglycerides. Participants with problems of avoidance and infrequency of sexual activity showed significantly lower levels of total, free and bioavailable testosterone when compared to participants without avoidance or infrequency problems. The +SD/+MetS group recorded the lowest SHBG levels. Conclusion: Testosterone and its bioactive components are associated with male libido as well as the metabolic syndrome. Low levels of free and bioavailable testosterone are true determinants of the MetS in men.
Determinants of sexual dysfunction among clinically diagnosed diabetic patients
William KBA Owiredu, Nafiu Amidu, Huseini Alidu, Charity Sarpong, Christian K Gyasi-Sarpong
Reproductive Biology and Endocrinology , 2011, DOI: 10.1186/1477-7827-9-70
Abstract: Sexual functioning was determined in 300 consecutive diabetic men (age range: 18-82 years) visiting the diabetic clinic of Tema General Hospital with the Golombok Rust Inventory of Sexual Satisfaction (GRISS) questionnaire, between November, 2010 and March, 2011. In addition to the socio-demographic characteristics of the participants, the level of glycosylated haemoglobin, fasting blood sugar (FBS) and serum testosterone were assessed. All the men had a steady heterosexual relationship for at least 2 years before enrolment in the study.Out the 300 participants contacted, the response rate was 91.3% after 20 declined participation and 6 incomplete data were excluded All the respondents had at least basic education, 97.4% were married, 65.3% were known hypertensive, 3.3% smoked cigarettes, 27% took alcoholic beverages and 32.8% did some form of exercise. The 69.3% SD rate observed in this study appears to be related to infrequency (79.2%), non-sensuality (74.5%), dissatisfaction with sexual acts (71.9%), non-communication (70.8%) and impotence (67.9%). Other areas of sexual function, including premature ejaculation (56.6%) and avoidance (42.7%) were also substantially affected. However, severe SD was seen in only 4.7% of the studied population. The perceived "adequate", "desirable", "too short" and "too long intra-vaginal ejaculatory latency time (IELT) are 5-10, 5-10, 1-2 and 15-30 minutes respectively. Testosterone correlates negatively with glycated haemoglobin (HBA1c), FBS, perceived desirable, too short IELT, and weight as well as waist circumference.SD rate from this study is high but similar to that reported among self-reported diabetic patients in Kumasi, Ghana and vary according to the condition and age. The determinants of SD from this study are income level, exercise, obesity, higher perception of "desirable" and "too short" IELT.Some of the consequences of diabetes include various medical [1], psychological [2], and sexual [3] dysfunctions. Among diabetic
Impact of Urban Agriculture on the Species Distribution and Insecticide Resistance Profile of Anopheles gambiae s.s. and Anopheles coluzzii in Accra Metropolis, Ghana  [PDF]
Joseph Chabi, Miracle C. Eziefule, Rebecca Pwalia, Joannitta Joannides, Dorothy Obuobi, Godwin Amlalo, Charlotte A. Addae, Iddrisu Alidu, Dominic Acquah-Baidoo, Samuel Akporh, Sampson Gbagba, Kwadwo K. Frempong, Melinda P. Hadi, Helen Pates Jamet, Samuel K. Dadzie
Advances in Entomology (AE) , 2018, DOI: 10.4236/ae.2018.63016
Abstract: Malaria incidence in urban areas has generally been low compared to rural areas but recent data indicate that urban malaria remains a public health problem. It is therefore important to understand the factors that promote urban malaria to help formulate future vector control strategies. This study compared Anopheles gambiae s.l. (A. gambiae s.l.) species composition, distribution and insecticide resistance mechanisms between vegetable and non-vegetable growing areas in Accra Metropolis. Four sites were selected within the city of Accra which comprised of two vegetable-growing and two non-vegetable growing areas. WHO susceptibility tests were carried out on adults A. gambiae s.l. reared from larvae collected from the sites. Five insecticides were tested and the A. gambiae complex, resistance genotypes and enzyme activities of each population were characterized. All A. gambiae s.l. populations tested were resistant to all the insecticides, but relatively lower mortalities were observed in the vegetable growing areas. The mortality against 0.05% deltamethrin was 2.6% (Opeibea) and 12.5% (Korle-Bu) for the vegetable growing areas and 36.2% (Achimota) and 38.9% (Mataheko) in the non-vegetable growing areas. Anopheles gambiae s.s. (95% of Opeibea population) and Anopheles coluzzii, (98% of Korle-Bu population) were the dominant species in the vegetable growing areas. The voltage-gated sodium channel (Vgsc-1014F) frequencies of all the populations were similar but the acetylcholinesterase (ace-1) frequencies were significantly lower (p < 0.05) in Korle-Bu and Mataheko populations. High level of P450s and esterases were observed in the A. gambiae s.l. from Opeibea than from the other areas. The contribution of urban agriculture in the development of insecticide resistance needs to be considered in the formulation of future vector control strategies alongside other domestic usages.
Alcohol Consumption Is Associated with Hypogonadism and Decreased Sexual Function in Ghanaian Diabetics  [PDF]
Huseini Alidu, William K. B. A. Owiredu, Nafiu Amidu, Christian Kofi Gyasi-Sarpong, Peter Paul Mwinsanga Dapare, Ahmed Tijani Bawah, Arnold Togiwe Luuse, Emmanuel Barima Agyemang Prempeh
Advances in Sexual Medicine (ASM) , 2017, DOI: 10.4236/asm.2017.73009
Abstract: Introduction: Alcohol usage has largely been seen as a risk factor for the development of sexual dysfunction as well as erectile dysfunction. Others have reported that prolonged alcohol usage and abuse is compatible with normal sexual function in the absence of endocrinological problems as well as hepatic dysfunction. About seventy five (75) percent of alcoholics have various sexual difficulties with improvements in sexual functions occurring after treatment of alcoholism and psychosexual therapy. It is evident from the various reports over the years that mild and occasional alcohol usage is not as much implicated in the causation of SD and its other forms as heavy, addictive or dependent alcohol usage. Alcohol usage has also long been linked to hypogonadism, testicular atrophy as well as leydig cell toxicity. Alcohol induced hypogonadism has been reported to resolve after withdrawal of alcohol use. Since both diabetes and alcohol usage have been strongly associated with both hypogonadism and sexual dysfunction, it is logical to expect that diabetics who frequently consume alcohol will have a worsened hypogonadal state and sexual function. This research therefore seeks to provide evidence of an association between alcohol consumption in diabetics and a worsened sexual dysfunction in comparison to diabetics who did not consume alcohol. Methods: Type II diabetic patients attending the Diabetic Clinic at the Maamobi General Hospital between the periods of January 2010 and March 2011 were consecutively recruited for this study. Diabetics with other known endocrinological diseases and physical disabilities were excluded from the study. Sexual function was assessed using the GRISS-M. Early morning fasting samples were used in lipid and testosterone profile assays. Results: Study participants who consumed alcohol recorded higher levels of triglycerides and LDL-Cholesterol. They also recorded significantly lower levels of bioavailable testosterone. Furthermore they also recorded higher scores for impotence, premature ejaculation, non-sensuality and infrequency but lower scores for avoidance and were about six times more likely to be infrequent in their sexual activity in comparison with those who did not consume alcohol. Conclusion: Alcohol consumption among diabetic males is associated with hypogonadism and has an impact on several domains of male sexual function. Diabetic males should be advised to avoid alcohol abuse in order to facilitate the management of diabetes associated sexual
Euler-Lagrange Elasticity: Differential Equations for Elasticity without Stress or Strain  [PDF]
H. H. Hardy
Journal of Applied Mathematics and Physics (JAMP) , 2013, DOI: 10.4236/jamp.2013.17004
Abstract:

Differential equations to describe elasticity are derived without the use of stress or strain. The points within the body are the independent parameters instead of strain and surface forces replace stress tensors. These differential equations are a continuous analytical model that can then be solved using any of the standard techniques of differential equations. Although the equations do not require the definition stress or strain, these quantities can be calculated as dependent parameters. This approach to elasticity is simple, which avoids the need for multiple definitions of stress and strain, and provides a simple experimental procedure to find scalar representations of material properties in terms of the energy of deformation. The derived differential equations describe both infinitesimal and finite deformations.

Euler-Lagrange Elasticity with Dynamics  [PDF]
H. H. Hardy
Journal of Applied Mathematics and Physics (JAMP) , 2014, DOI: 10.4236/jamp.2014.213138
Abstract: The equations of Euler-Lagrange elasticity describe elastic deformations without reference to stress or strain. These equations as previously published are applicable only to quasi-static deformations. This paper extends these equations to include time dependent deformations. To accomplish this, an appropriate Lagrangian is defined and an extrema of the integral of this Lagrangian over the original material volume and time is found. The result is a set of Euler equations for the dynamics of elastic materials without stress or strain, which are appropriate for both finite and infinitesimal deformations of both isotropic and anisotropic materials. Finally, the resulting equations are shown to be no more than Newton's Laws applied to each infinitesimal volume of the material.
Linear Algebra Provides a Basis for Elasticity without Stress or Strain  [PDF]
H. H. Hardy
Soft (Soft) , 2015, DOI: 10.4236/soft.2015.43003
Abstract: Linear algebra provides insights into the description of elasticity without stress or strain. Classical descriptions of elasticity usually begin with defining stress and strain and the constitutive equations of the material that relate these to each other. Elasticity without stress or strain begins with the positions of the points and the energy of deformation. The energy of deformation as a function of the positions of the points within the material provides the material properties for the model. A discrete or continuous model of the deformation can be constructed by minimizing the total energy of deformation. As presented, this approach is limited to hyper-elastic materials, but is appropriate for infinitesimal and finite deformations, isotropic and anisotropic materials, as well as quasi-static and dynamic responses.
Page 1 /149544
Display every page Item


Home
Copyright © 2008-2017 Open Access Library. All rights reserved.