419 research outputs found
Les comportements écologiques des dirigeants des entreprises tunisiennes
À la fin des années 1980, plusieurs entreprises tunisiennes, en réaction essentiellement à la législation environnementale, ont commencé à élaborer des initiatives environnementales en optant pour des niveaux d’engagements environnementaux différents. L’objectif de cette recherche est d’identifier les comportements écologiques des dirigeants des entreprises tunisiennes en se basant sur leur niveau d’engagement environnemental. Sur un échantillon de 55 entreprises, les résultats montrent l’existence de trois comportements : défensif, conformiste et citoyen. Les résultats montrent aussi que la taille joue un rôle dans l’adoption d’un comportement plus responsable. En revanche, aucune relation n’a été trouvée entre le comportement écologique et le secteur d’activité.In 1988, some Tunisian firms, essentially in reaction with the environmental regulation, have instituted environmental initiatives. The objective of this research is to classify the Tunisian managers based on their environmental commitment. In a sample of 55 firms, the results show the existence of three groups based on environmental commitment; reactive, conformist and citizen managers. Firm size had a major impact on the environmental commitment. But no relationship was found between environmental commitment and activity sector
LES DETERMINANTS DES CHOIX COMPTABLES RELATIFS AUX ELEMENTS IMMATERIELS CAS DES ENTREPRISES TUNISIENNES
Cet article examine les facteurs susceptibles d'influer sur la décision d'activation des dépenses immatérielles dans un pays émergent. L'analyse empirique (régressions linéaires et logistiques), portant sur les données relatives à l'année 2003 et sur 50 entreprises cotées et non cotées, suggère que cette pratique permette essentiellement de réduire les contraintes d'endettement. Cependant, les hypothèses de réduction des coûts politiques, de maximisation de la rémunération et de valorisation boursière n'ont pas été confirmées.activation des dépenses immatérielles; contraintes d'endettement; opportunisme managérial; coûts politiques
Design and Simulation of Modular Multilevel Converter Fed Induction Motor Drive
Traditional modular multilevel converter (MMC) applications in medium voltage induction motor drive are difficult, particularly at low speeds because of the higher magnitude of the voltage ripple of the sub-module capacitor. This paper uses a hybrid MMC, particularly at low frequencies, to achieve a lower peak-to-peak voltage ripple of the sub-module capacitor. The vector control strategy with the closed-loop speed control indicates an accurate and wide-speed range. MATLAB / Simulink is used to simulate and obtain the simulation results of hybrid and traditional MMC with induction motor drive and compare from the standpoint of capacitor voltage ripple. The results are shown the reduction of peak-to-peak voltage ripple of the sub-module capacitor as the hybrid MMC is operated
Heavy Metals Concentration in Urban Soils of Fallujah City, Iraq
Twenty samples were collected from the urban soils in Fallujah City in order to determine concentrations, spatial distribution and contamination assessment of heavy metals such as Cu, Zn, Ni, Pb, Ni, Fe, Mn, Cd, Co and Cr. The mean concentrations are as follows : 235.77?g/g for Fe, 24.09?g/g for Mn, 11.59?g/g for Cr, 8.96?g/g for Ni, 5.50?g/g for Zn, 3.82?g/g for Pb, 3.43?g/g for Co , 2.01?g/g for Cu and 0.64?g/g for Cd. To assess metal contamination in urban soils, soil quality guidelines were applied. The mean concentration of Cu, Zn, Ni, Pb, Ni, Fe, Mn, Co and Cr did not exceed and Cd exceeded the USEPA guideline. A similar spatial distribution patterns between the heavy metals were found indicating that these metals were from the same sources. The metal contamination in the soils was also evaluated by appling enrichment factor (EF), pollution load index (PLI), integrated pollution load index (IPLI) and geoaccumulation index (Igeo). Based on enrichment factor (EF) , the urban soils in Fallujah city are extremely high enriched with Cd and Co, very high enriched with Ni and Cr and Pb, Cu and Zn exhibit significant enrichment. to IPLI values, urban soils in Fallujah are lowly polluted with heavy metals. According to Igeo, the urban soils in Fallujah City are uncontaminated to slightly contaminated by Cd. The sources of Cd in soil may be from industrial and anthropogenic activities. Keywords: Urban soils, Heavy metals, Fallujah city
Content delivery network for secure of software defined networking by using IPv4, OpenFlow, and ALTO
Software defined networking is a programmability function network by easiness for maintenance and configuration. The administrators of network can change the traffic rules during the commuting process. SDN is an arising network structure with programmability and centralization and this leads to introduce potential security concerns. Though the TLS ability support secure for control plane but computationally aggravating and complex to configure as well as not compatible with OpenFlow protocol. For this reason, a content delivery network can be used to increase the ability of network services dynamically and automatically. In order that relieve the threat we proposed architecture for SDN depending on CDN. In our proposed architecture, we use application layer traffic optimization (ALTO) protocol to be as servers enable mapping for the network to produce a summarized vision. We also hide the identity of the forwarding devices by take advantage of IPv4 and OpenFlow transaction identification fields into the control packets through implement of two authentication structures via efficient Salsa20 stream cipher. Finally, the work results explain the proposed architecture can efficiently eliminate of attack types and provide more detectability to attackers
Bilateral acute angle closure glaucoma after hyperopic LASIK correction
AbstractAcute angle closure glaucoma is unexpected complication following laser in situ keratomileusis (LASIK). We are reporting a 49-years-old lady that was presented to the emergency department with acute glaucoma in both eyes soon after LASIK correction. Diagnosis was made on detailed clinical history and examination, slit lamp examination, intraocular pressure measurement and gonioscopy. Laser iridotomy in both eyes succeeded in controlling the attack and normalizing the intraocular pressure (IOP) more than 6months of follow-up. Prophylactic laser iridotomy is essential for narrow angle patients before LASIK surgery if refractive laser surgery is indicated
La Comptabilisation des Dépenses Immatérielles: Quels Déterminants Empiriques ?
Cet article examine les facteurs susceptibles d'influer sur la décision d'activation des dépenses immatérielles des entreprises tunisiennes cotées et non cotées. L'analyse empirique (régressions linéaires et logistiques) porte sur les données relatives à l'année 2003 et sur 50 firmes cotées et non cotées suggère que cette pratique permet essentiellement de réduire les contraintes d'endettement et d'informer les actionnaires sur la qualité des projets. Cependant, l'hypothèse de réduction des coûts politiques n'a pas été confirmée dans le contexte tunisien.activation des dépenses immatérielles; contraintes d'endettement; opportunisme managérial; opportunités d'investissement;coûts politiques
Proposing a security system for the VPN through design and implementation of a scheme for android and IOS mobiles based on two-factor authentication
A virtual private network (VPN) is a network, but a virtual network means that it creates a virtual bridge between the user and the server located somewhere across the world, and this network is private because to connect the connection with it you must have an account and password. The idea of VPN arose to protect its communications from industrial espionage, because there are very easy ways to penetrate a network and steal the information circulating in it. Data transmission encryption protocols and tunneling systems are used in order to secure the transfer of information between two points back and forth, so their data is encrypted and protected. Hacking the VPN is a very dangerous thing because of the importance and privacy of the data. Therefore, special systems must be provided for the VPN to suit the network's work scenarios with high security. In our work, we proposed a private authentication system for the VPN network that provides high security with fast execution and reliability based on two factors authentications: Using the varieties of authentications method, robust VPNs screen everybody who will tries to sign in. An authentication system was designed based on a special user interface that provides an easy environment for choosing two passwords in two different stages of registration and authentication. The proposed system was implemented on Android and iOS devices. The proposed system was evaluated through experiments with 720 participants with 3600 system entry processes, then the proposed system was tested in terms of its ability to break and resistance to different types of attacks. Where it was tested by 1900 attacks at different times with participants who were randomly selected from the main sample of participants during the implementation period of 30 days through using the modern types of mobile devices
The Role of CorrugateDrain In Decreasing Postoperative Complication Of Penile Fracture Surgery
الغرض من الدراسة: هو دراسة دور المصرف المتجعد والذي يقوم بأستخدامه البعض من جراحي الجراحة البولية بعد إجراء عملية تصحيح كسر القضيب للتقليل من التورم والالام والانحراف في القصيب.
طريقة العمل : دراسة مقارنة مقطعية أجريت في شعبة الجراحة البولية في مستشفى الحلة الجراحي، عشرون مريضا اعمارهم تتراوح بين 21الى 40سنة كانوا يعانون من كسر القضيب للفترة من ادار 2008 الى نيسان 2011.
ادخلوا الى شعبة الجراحة البولية في مستشفى الحلة التعليمي العام، تم إجراء تداخل جراحي فوري لكل المرضى ,حيث تم وضع المصب المتجعد الى عشرة من هؤلاء المزضى ولم يتم ذلك للعشرة الاخرين. جميع المرضى تم متابعتهم مابعد العملية ولفترة لاتقل عن ثلاثة أشهر وخصوصا بمايتعلق بتورم وتشوه القضيب وايضا الالام والوظائف الجنسية.
النتائج: بما يتعلق بأعمار المرضى الذين يعانون من كسر القضيب والمشموليين في الدراسة , كان هناك 11مريض اعمارهم تتراوح بين (20-30) سنة , 7 من المرضى كانت أعمارهم بين (31-45) سنة ,2 من المرضى كانت أعمارهم تتراوح بين (46-60) سنة. وبا يتعلق بالحالة الزوجية للمرضى , 15 مريض كانوا متزوجين وفقط ٥ من المرضى كانوا غيز متزوجين. لم يعاني أي مريض من المرضى الذين تم إجراء لهم عملية تصحيح كسر القضيب وتم وضع لهم المصب المتجعد من اي تورم في القضيب ولكن مريض واحد فقط من المرضى الذي تم اجراء لهم عملية تصحيح الذكر ولم يتم وضع لهم المصب المتجعد كان قد عانى من تورم القضيب. بما يتعلق بالالم ما بعد عملية تصحيح كسر القضيب ,6مرضى فقط كانوا قد من الالم من المجموعة الذي تم وضع لهم المصب المتجعد بينما مريضان فقط من المرضى الذي لم يتم وضع لم المصب المتجعد كانوا قد عانوا من الالم مابعد عملية تصحيح كسز القضيب.
الاستنتاج: من النتائج المستوحاة لهذا البحث إن إستخدام المصب المتجعد مابعد عملية تصحيح كسر القضيب غير مفيد بالتقليل من التورم او تقليل الالم او إنحراف الذكر مابعد عملية تصحيح كسر القضيبObjective:tostudy the role of corrugate drain (which is used by some urosurgeons) followed surgical correction of fractured penis in decreasing post operative complications such as penile swelling, pain and curvature.
Patient and method:comparative cross sectional study was carried out at the urological department of Al-Hilla teaching hospital from March 2008 to April 2011.
Twenty male patients (age between 21-40 years) admitted to the urological department in Al-Hila teaching hospital suffering from penile fracture from March 2008 to April 2011 were included in this study.
Immediate surgical repair done to all those patients ,corrugate drain put post operatively for 10 patients while the remaining 10 patients without drains.
All patients are fallowed for at least 3 months regarding postoperative penile swelling, deformity, pain and sexual function.
Result:regarding age distribution of patients suffering from fracture penis, from twenty patients included in this study 11 patients their agerange from (20-30)years, 7 patients their age group range from (31-45)years and only 2 patients their age range from (46-60)years. Fifteen patients are married and only 5 patients are unmarried. No one develop postoperative penile swelling in patients with corrugate drain and only one patient develops swelling in patients without corrugate drain. Regarding postoperative pain, in patients surgically corrected with drain, 6 patients develop pain and only 2 patients surgically corrected without drain develops pain.
Conclusion:No beneficial effect of corrugate drain in decreasing postoperative penile swelling or curvature and on the other hand it increase post operative penile pai
Transmission lines modelling based on RLC passive and active filter design
This paper presents a transmission line (TL) modelling which is based upon vector fitting algorithm and RLC passive filter design. Frequency Response Analysis (FRA) is utilised for behaviour prediction and fault diagnosis. The utilities of the measured FRA data points need to be enhanced with suitable modelling category to facilitate the modelling and analysis process. This research proposes a new method for modelling the transmission line based on a rational approximation function which can be extracted through the Vector Fitting (VF) method, based on the frequency response measured data points. A set of steps needs to be implemented to achieve this by setting up an extracted partial fraction approximation, which results from a least square RMS error via VF. Active and passive filter design circuits are used to construct the model of the Transmission line. The RLC design representation was implemented for modelling the system physically while MATLAB Simulink was used to verify the results
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