المستودع الرقمي لـجامعة طرابلس

Abstract

The quadruple-tank process has been widely used in control literature to illustrate many concepts in multivariable control, particularly, performance limitations due to multivariable right half-plane zeros. The main feature of the quadruple-tank process is the flexibility in positioning one of its multivariable zeros on either half of the‘s’ plane A nonlinear and linear dynamic model for the quadruple-tank process are derived. The nonlinear model is derived from Johansson nonlinear dynamic system and describes the complicated dynamics of the physical plant when the system is setting in the non-minimum phase. The simulation results show that PID controllers have acceptable performances especially when the system is minimum-phase system while in the non-minimum-phase the controller is poor. Also it is shown that the linear quadratic Gaussian with loop transfer recover (LQG/LTR) is better than PID controller when the system is minimum-phase while in the non-minimum-phase the controller is not acceptable because (LQG/LTR) compensators generally cannot be designed for non-minimum-phase plants. Simulation results show that the proposed Decentralized fuzzy logic controller has a remarkable performance for tracking the multi step reference trajectories while at the same time it is robust against voltage changes. The Simulation results confirm the effectiveness of the proposed control methodology.
أبوبكر عبدالكريم أبو شاقور (2010)

Abstract

The research discusses the passive solar energy in cooling the internal gaps, using architectural and urban techniques In the traditional architecture In Libya, aiming to reach to required thermal comfort for humans, particularly in the high temperature areas, It could be done through four chapters in the research, so that shall contain a part of the research content, in addition to results and recommendation, so that shell discuss: First chapter: whereas the research discusses the study of climate elements, which are considered as the most effecting factors on thermal comfort, plus demonstration of climate and climate regions in Libya. Thereafter, the study of traditional architecture in different regions of Libya (cost, mountains, desert), clarification of their most important characteristics and features at architect and urban levels, used materials and methods of construction of the same, then comparison of regions to reach to features of each region. Second chapter: this chapter shall discuss study of humans comfort, and sources of thermal gain and loss between the human body and its ambient, especially by climate factors, the most significant study of thermal gain and loss sources of the building form the direct sun rays, via walls and roofs and movement of the air. Third chapter: the sun rays are deemed the most important climate elements effecting the architectural and urban, which generate other climate elements, such as air movement and humidity …etc, which in turn impact the human thermal comfort. Thus, this chapter focused on study of passive cooling techniques, using urban and architectural technologies, to limit the effect of sun rays, prior to its reach to the building, or to limit its penetration through walls and roofs, passing by historical stops of using passive cooling techniques. Fourth chapter: Addresses this chapter analytical study applied to the methods and techniques of cooling using solar energy passive in traditional architecture, by examining and analyzing the most important of these techniques and treatments Urban and architectural in different regions (coastal, mountain, desert) and benefit from and applied in the local architecture. Finally: the search to a set of findings and recommendations to the effect that he must return to traditional architecture and technologies and processes and take advantage of them to maintain the legacies of urban and architectural history, and development in the local construction and architecture.
يوسف مفتاح الهمالي (2013)

Abstract

This research study aims to find out the impact of the privation of The Libyan commercial banks on developing the level of accounting disclosure in The Libyan commercial banks. In this study, the effect of the privatization of The Libyan commercial banks was tested on accounting disclosure with its Financial statements and reports such as: balance sheet, income statement, cash flows statement, and the statement of changes in equity and accounting methods and policies.To achieve the aim of the study. a sample of participants form two Libyan commercial banks “ AL-wihda bank and AL-Sahari Bank” were chosen randomly. The participants were general managers, accountants, auditors and some employees working in those two banks. The Libyan environment was chosen by The researcher as a field study.A questionnaire was prepared to collect data. The questionnaire was distributed to the participants of the study to find out their opinion about the effect of the privatization of the Libyan commercial banks on accounting disclosure in Libyan commercial banks, After that data were collected, Classified and analysed, Some software programmes were used for the analysis of data such as the statistics software (SPSS), Cronbach alpha (α) Test for the validity and authenticity of data collected, the relative frequency distribution, wilcoxon Test and (T) Test. The result of this study indicated that, the privatization of the Libyan commercial banks plays a role in developing the accounting disclosure with its financial and reports in commercial banks in the Libyan environment. The most prominent conclusions were as the following:The privatization of The Libyan commercial banks can improve the level of accounting disclosure in the financial statement ( income statement, Cash flows statement) with excluding some items such as ( investment risk reserve, net gains from financial securities, net gains from investment securities, losses on loans and advances – ordinary share profits, time deposits with foreign banks. It was also Concluded that the privatization of commercial Libyan banks does not improve the level of accounting disclosure in statement of changes in equity , Also, the privatization of the Libyan commercial banks improves the level of accounting disclosure of the accounting methods and policies except ( the disclosure of the total secured obligations and the nature of pledged assets as a security and its recorded value) . From the field visits the researcher noted that there was a problem in access to information at an appropriate time because of the delay in preparing annual reports . In the light of the findings of the present study, it is recommended to develop and increase the disclosure of Investment risk reserves, net gains arising from financial securities, the net gains arising from investment securities, losses on loans and advances – ordinary share earnings, and deposits with other banks. It is also recommended to prepare and produce financial statements and reports at an appropriate time at the end of financial year, and publish them in order to help the investor to study it and make decisions based on these statements and reports.
إسماعيل بشير علي سلطان (2012)

Abstract

This study has discussed subject of Relation of Banking Marketing with financial performance of the bank, hence it has become clear that procedure of banking marketing is not performed. (Problem of thesis)So, we treated the said problem through issuance the detailed hereinafter hypothesis:There is relation between the banking marketing and financial performance of the bank.-The first branch hypothesis: indicates extent of practice job of banking marketing.-The second branch hypothesis: indicates extent of efficiency of financial performance of the bank. The study depended on complete survey of place of study (bank of commerce and development, including making random sample from working staff in the said bank. Tools of survey were through using questionnaire, but study depended on method of financial and statistical analysis including analysis of financial ratios such as monetary flow, ratio of profits, ratios of loaning, and this questionnaire subjected to study.The results of study assured necessity of banking marketing for banks in order to increase its competitive capability and possessing means of technology, in addition to contribution of the banking marketing in raising of mechanism of management and technological development through advanced electronic services, and helps in increase of banks profits in order to meet requirements of competition , and resistance in front of huge banks.The study issued some recommendations represented in direction towards operations of banking marketing on consideration pioneer phenomena related to huge banking corporations aiming at raising level of its competitive capability, and improvements in world where the economics blocks prevail , in addition to Necessity of making training courses for working staff in the banks , and updating independent department for marketing in the bank.
صلاح رمضان السني (2009)

Abstract

This Thesis overviews the methods for calculating the stress intensity factor and employs the stress and displacement methods in the current study. The model used simulates a cracked rectangular plate which is subjected to tensile stress. The Finite element method is used to calculate inplane displacement due to applied loads. As a post processing the stress and stress intensity factor over the plate was calculated. The results show that the singularity exists at the crack tip and the components of stress and approach infinity as the crack tip approach. The comparison of the current study to theoretical and other numerical results shows a good agreement and reliability of the program. The thesis consists of five chapters, the first chapter, presents general over view and historical al review. The second chapter demonstrates the theoretical basis in fracture mechanics. The third chapter involves the numerical solution using F.E.M. The fourth chapter demonstrates a case study and the results and discussion of the obtained results. The fifth chapter concludes the work and gives recommendations.
محمد كامل الشيخ (2009)

Abstract

Traditional compact urban fabric patterns is type of urban fabric that characterized by its organic structure integrated with the natural environment. The building blocks in this type are attached interspersed with interior courtyards within and between buildings. Streets and alleys are narrow, not straightforward and with closed endings. This system is common in the old traditional cities. Traditional compact urban fabric is classified according to the traffic network into forked or regular this research deals with the study and analysis of the concept of traditional compact urban fabric from the social perspective. It is a study of the social aspects affecting and affected by the built environment related to daily life within the prevailing social systems which is a man-made laws laid down by a group of people to organize their lives. Due to the multiplicity of the fields of social system, the researcher identified systems that are thought to have a clear impact on the built environment in the study area, which are the tribal system, the family system and the management of traditional community (Alhessbah and Aezzabah) The old town of Jadu was chosen as a case study. The study addresses the following issues. First- the concept and the characteristics of traditional compact urban fabric, were defined through the study of historical examples. Secondly - the physical structure of traditional compact urban fabric and the impact of social factors in the formation of this structure. Thirdly, field study which limited to the old town of Jadu which consists of two neighborhoods Tarkeen and Amgail. The porpose of field study is to analyze the impact of specific social systems on the built environment in the study area
نادية خليفة الحارس (2014)

Abstract

Voice over IP (VoIP) uses the Internet Protocol (IP) to transmit voice as packets over an IP network, like the Internet, Intranets and Local Area Networks (LAN). Here the voice signal is digitized, compressed and converted to IP packets and then transmitted over the IP network. However, at the receiving end, some packets may be missed in its way due to network congestion. This packets loss degrades the quality of speech at the receiving end of a voice transmission system in the IP network. Since the voice transmission is a real time process, the receiver cannot request for retransmission of the missing packets. High speed networks provide real time variable bit rate service with packet loss requirements. The burstiness of the correlated traffic makes dynamic buffer management highly desirable to satisfy the Quality of Service (QoS) requirements. This thesis presents an algorithm to improve and optimize the Adaptive Buffer Allocation Scheme to deal with input traffic based on loss of consecutive packets in data streams and buffer occupancy levels. Buffer is designed to allow the input traffic to be partitioned into different priority classes, and based on the input traffic behavior it controls the threshold dynamically. This scheme allows input packets to enter into buffer if its occupancy level is less than the threshold value for priority of that packet. The threshold is dynamically varied in runtime based on packet loss behavior. The performance evaluation is carried out using simulation and is carried out for two and multiple priority classes of the input traffic "real time and non real time classes". The simulation results show that the Modified Adaptive Partial Buffer Sharing (ADPBS) has better performance than Adaptive Partial Buffer Sharing under the same traffic conditions.
اسماء احمد الكيش (2010)

Abstract

Wind turbines are the means of converting wind energy into electrical energy. It is not unexpected that certain brands of horizontal wind turbines are optimally designed for certain wind speed regimes prevailing at certain sites. It has been the objective of this study to find out whether it is possible to design a wind turbine that is more suitable for a site of lower annual mean wind speed such as the western coast of Libya. In achieving this objective, use was made of a typical wind turbine aerodynamic design and performance analysis procedure together with actual wind speed data recorded at the city of Misurata.Based on the annual wind energy yield obtained from different designs of wind turbines having different rated wind speeds and different blade design tip speed ratios, this study indicates that the decrease of the rated wind speed leads to a continuous increase of annual energy yield as well as an increase of the cost of the wind turbine. Therefore the optimum value of rated wind speed for this site may only be determined as a compromise between added wind energy yield and added cost. Moreover, for any given rated wind speed this study indicates that a blade design tip speed ratio equal to six seems to be the optimum value for the given site.
محمد على نايلي (2015)