DSpace 8

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Communities in DSpace

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Now showing 1 - 5 of 10

Recent Submissions

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Étude comparative de l’évaluation phytochimique et des activités biologiques d’une espèce végétale du Nord-Est algérien
(Université Echahid Cheikh Larbi Tebessi. Tébessa, 2026-06-24) Lamari Sarra
La valorisation du patrimoine floristique algérien, riche d'environ 3000 espèces, constitue un enjeu majeur pour la découverte de biomolécules actives. Cette étude explore la variabilité chimique et biologique de Teucrium polium L. récoltée dans cinq régions du Nord-Est algérien. La méthodologie combine une extraction séquentielle (HE et solvants de polarité croissante), une caractérisation par UV-VIS-NIR, GC-MS/MS et LC-ESI-MS/MS, ainsi qu'une évaluation biologique in vitro (antioxydante, enzymatique, anti-inflammatoire, SPF) et in silico (ADMET- Docking). Les résultats démontrent que la nature du sol influence significativement la composition chimique et la répartition des métabolites secondaires de la plante, la caractérisation chimique a identifié entre 59 et 68 composés volatils dans l’huile essentielle et a révélé la prédominance de l'acide coumarique, du thymol et du bêta-carotène dans l’extrait méthanolique. Les tests biologiques et le docking ont confirmé que l'extrait méthanolique possède les meilleures propriétés antioxydantes avec des valeurs d'IC50 variant de 7,79 à 111,94 μg/mL selon les régions. À l'inverse, l'étude a révélé une absence d'activité anti-inflammatoire in vitro (test de la BSA) ainsi qu'une faible inhibition des cholinestérases variant de 539±1,85 à 638,7±1,23 μg/mL. L'approche in silico a mis en évidence une bonne biodisponibilité orale potentielle et a confirmé la sécurité d'emploi des composés, avec 94 % des molécules présentant une faible toxicité aiguë (DL50 >2000 mg/kg), tout en révélant des affinités de liaison remarquables avec la cible COX-2. En conclusion, ce travail démontre que la variabilité bioclimatique impacte directement la plasticité métabolique de Teucrium polium. L'extrait méthanolique s'impose comme le candidat le plus prometteur pour des applications antioxydantes et cosmétiques, justifiant la nécessité de futures études précliniques in vivo.
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Design and Optimization of Antenna for Next Generation
(University of echahid cheikh larbi tebessi – tebessa, 2026-09-15) Ahmed Ould Mohamed Salem
The rapid evolution of fifth-generation (5G) and beyond fifth-generation (B5G) wireless communication systems has significantly increased the demand for compact, high-performance, and computationally efficient millimeter-wave (mmWave) antenna architectures. However, the design of mmWave Multiple-Input Multiple-Output (MIMO) antennas remains highly challenging due to the simultaneous requirements of high gain, wide bandwidth, compact in- tegration, low mutual coupling, and reduced computational complexity. In addition, conven- tional full-wave electromagnetic optimization techniques are computationally expensive and time-consuming, particularly for iterative antenna-design procedures. To address these chal- lenges, this doctoral thesis proposes a hybrid electromagnetic and physics-guided artificial intelligence framework for the design, optimization, and rapid synthesis of high-performance mmWave MIMO antennas. The proposed methodology combines advanced electromagnetic engineering techniques with physics-guided neural learning strategies to improve both an- tenna performance and computational efficiency. In the first part of this work, a compact four-element 28 GHz MIMO antenna system was designed, fabricated, and experimentally validated for 5G mmWave applications. The proposed antenna architecture integrates De- fected Ground Structures (DGS) and a Frequency Selective Surface (FSS) superstrate to re- duce mutual coupling and enhance radiation performance. The incorporation of the FSS su- perstrate at an optimized distance of 7 mm improved the antenna gain from 4.8 dBi to 8.4 dBi, corresponding to an enhancement of approximately 75% (+3.6 dBi). In addition, the proposed decoupling configuration achieved port-to-port isolation exceeding 25 dB while maintaining satisfactory MIMO diversity performance. To overcome the computational limitations of conventional full-wave solvers, a dual-network Physics-guided AI framework was developed for inverse antenna synthesis and forward electromagnetic prediction. The inverse synthesis model was trained using 8,000 analytically generated samples derived from Transmission- Line Model (TLM) equations, while the forward analysis model was independently trained using 475 high-fidelity CST full-wave simulation samples. By integrating electromagnetic prior knowledge into the neural learning process, the proposed framework preserves physical consistency while improving prediction accuracy and computational efficiency. The devel- oped framework reduced the antenna synthesis time from several hours of full-wave sim- ulations to only a few milliseconds. The inverse synthesis model achieved sub-millimeter prediction accuracy with a Root Mean Squared Error (RMSE) of Wp (≈ 0.00156 mm) and Lp (≈ 0.00169 mm) and a regression coefficient of (R2 = 0.99999), while the forward predic- tion model limited the relative resonant frequency prediction error to only 0.08% compared with CST full-wave simulation results. Overall, the proposed hybrid electromagnetic–AI framework establishes a scalable and computationally efficient methodology for intelligent antenna synthesis and multi-objective optimization in next-generation wireless communica- tion systems, with strong applicability to future 5G-Advanced and 6G mmWave technologies.
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Miniaturisation des Antennes Patch à l'Aide des Métamatériaux pour les Applications Sans Fil
(UNIVERSITE DE ECHAHID CHEIKH LARBI TEBESSI, 2026-06-09) Nabet Chourouk / Khediri Ramzi / encadré par FERROUDJI Karim
This final year project focuses on the design, optimization, and miniaturization of a high-performance planar patch antenna for modern communication applications (5G, WiMAX, 4G/LTE, IoT, …). The main objective of this research was to overcome the major theoretical limitation that systematically links reducing the physical size of antennas to a degradation in their performance. To meet this challenge, we exploited the novel electromagnetic properties of metamaterials. The scientific approach adopted consisted of first designing a conventional reference antenna optimized to resonate at an initial frequency of 5 GHz. Subsequently, a complementary split-ring resonator (CSRR) was precisely integrated into the ground plane. The electromagnetic coupling thus generated made it possible to confine the energy and successfully shift the fundamental frequency to 2.50 GHz, thereby achieving a remarkable miniaturization rate without compromising the overall radiative integrity of the structure. Numerical simulations performed using ANSYS HFSS software confirm the robustness and technical viability of the proposed architecture, demonstrating that it constitutes an efficient
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دور حوكمة الشركات في رفع تنافسية المؤسسة الاقتصادية دراسة حالة شركة الإسمنت تبسة
(جامعة الشهيد الشيخ العربي التبسي تبسة, 2026) ياسر، صالحي; ياسر، شريط; أ. حمايدية مروة
تهدف هذه الدراسة إلى إبراز مدى مساهمة حوكمة الشركات في رفع تنافسية مؤسسة الأسمنت تبسة، من خلال التعرف على حوكمة الشركات ومبادئها المتمثلة في وجود أساس فعال للحوكمة، أصحاب المصالح وضمان حقوق المساهمين الإفصاح والشفافية، ومسؤولية مجلس الإدارة، والتعرف على مختلف مؤشرات التنافسية وكذا تحديد مختلف إستراتيجياتها بالإضافة إلى توضيح العلاقة بين حوكمة الشركات و تنافسية المؤسسة، وقد تم استقصاء آراء الموظفين بمؤسسة الإسمنت - تبسة ومن ثم معالجتها إحصائيا من خلال إعداد نموذج الإنحدار البسيط وتفسيره وقد توصلت الدراسة إلى وجود أثر ذو دلالة إحصائية لحوكمة الشركات على رفع تنافسية المؤسسة عند مستوى معنوية (0.05). الكلمات المفتاحية حوكمة الشركات، تنافسية المؤسسة، الفعالية، أصحاب المصالح، الإفصاح والشفافية= This study highlights corporate governance's role in boosting the Tebessa Cement Company's competitiveness. It examines governance principles: solid foundations, shareholder rights, disclosure, transparency, and board responsibility. It identifies competitive indicators and strategies while exploring the governance-competitiveness link. Employee opinions from the Tebessa Cement Company were analyzed using a simple linear regression model. The study found a statistically significant impact of corporate governance on company competitiveness at a 0.05 significance level.
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أثر ادارة المعرفة في تعزيز الميزة التنافسية
(جامعة الشهيد الشيخ العربي التبسي تبسة, 2026) دعاء، جابري; جابري، صبرينة; أ. هاني عبد المالك
تهدف هذه الدراسة إلى إبراز أثر إدارة المعرفة بعملياتها الثالثة - اكتساب المعرفة ومشاركة المعرفة وتطبيق المعرفة - في تعزيز الميزة التنافسية في مؤسسة األسمنت بتبسة TCC، وذلك بواسطة توزيع استبيان على عينة من الموظفين حجمها 05 موظفاً، وقد تبين أن إدارة المعرفة تساهم في تحسين األداء التنظيمي ورفع جودة اإلنتاج ودعم األداء التنافسي للمؤسسة، كما تبين أن مؤسسة TCC كفرع من فروع المجمع الصناعي العمومي GICA تستحوذ على الحصة السوقية األكبر في السوق الجزائرية. وقد أسفرت الدراسة التطبيقية على وجود تأثير إيجابي لعملية تطبيق المعرفة فقط في تعزيز الميزة التنافسية للمؤسسة، ويمكن تفسير ذلك بأن عمليتي اكتساب المعرفة ومشاركتها يتمان بشكل روتيني ال يضيف قيمة جديدة، بينما يتم تطبيق خبرات قديمة في األداء واتخاذ قرارات وحلول فورية وفردية. وفي األخير يمكن اقتراح تثمين األثر اإليجابي لعملية تطبيق الخبرات بتمكين الموظفين ذوي الخبرات، وكذا معالجة ضعف مساهمة عمليتي اكتساب المعرفة ومشاركتها بتطوير برامج التدريب والتكوين ودمج العمليتان في نظام الحوافز، وكذا مواصلة التحسين المستمر ألن الحصة السوقية الكبيرة ال تلغي ضرورة تعزيز الميزة التنافسية= The study aims to highlight the impact of knowledge management, with its three processes (acquiring knowledge, sharing it, and applying it), on enhancing the competitive advantage of the Tebessa Cement Company (TCC), using a questionnaire distributed to a sample of 50 employees. Key findings include: knowledge management contributes to improving organizational performance, raising production quality, and supporting the company's competitive performance; and TCC, as a subsidiary of the public industrial group GICA, holds the largest market share in the Algerian market. The applied study revealed a positive effect of knowledge application alone on enhancing the company's competitive advantage. This can be explained by the fact that knowledge acquisition and sharing are routine processes that do not add new value, while outdated expertise is applied in performance, leading to immediate and individualized decision-making and solutions. Finally, the following suggestions are made: maximizing the positive effect of knowledge application by empowering experienced employees, addressing the limited contribution of knowledge acquisition and sharing by developing training programs and integrating these processes into the incentive system, and continuing continuous improvement, as a large market share does not negate the need to bolster competitive advantage.