Exact Spin Coherent State Path Integral for a Neutral Spinning Particle Interacting with a Helical Magnetic Field

Mekki Aouachria 한국물리학회 2011 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.58 No.4

Exact solutions for a neutral spinning particle interacting with a helical magnetic field have been found by using a path integral formalism. The propagator is first written in the standard form ∫D(path)expi/ħS(path) by replacing the spin by unit vectors aligned along the polar and azimuthal directions (θ,φ). Then, we use the phase space and rotations in the space of spin coherent states to simplify the calculations. Thus, the exact energy spectra with corresponding wave functions are deduced.

A UHF/UWB Monopole Antenna Design Process Integrated in an RFID Reader Board

Mekki Kawther,Necibi Omrane,Lakhdhar Saoussen,Gharsallah Ali 한국전자파학회 2022 Journal of Electromagnetic Engineering and Science Vol.22 No.4

This paper presents a new circular monopole antenna with triple-band characteristics that can operate in both ultra-high frequency (UHF) and ultra-wideband (UWB) and can be integrated into a radio-frequency identification (RFID) system reader board. The antenna was built with a patch and a coplanar waveguide (CPW) feed microstrip line to meet the UHF/UWB bandwidth requirements for RFID applications. The designed antenna has a size of 70 mm × 60 mm × 0.8 mm. CST Microwave Studio simulations were used to validate the proposed antenna, which had a maximum gain of 4.8 dBi. Furthermore, the designed antenna had a radiation pattern that spanned the full working band. To interact with RFID tags, the antenna was built and installed into the RFID reader board. The simulation and measurement findings showed good agreement. Experiments indicated that the UHF-RFID performance of the monopole antenna was comparable to that of existing commercial solutions.

Generalised Ricci Solitons on Sasakian Manifolds

Mekki, Mohammed El Amine,Cherif, Ahmed Mohammed Department of Mathematics 2017 Kyungpook mathematical journal Vol.57 No.4

In this paper, we show that a Sasakian manifold which also satisfies the generalised gradient Ricci soliton equation, satisfying some conditions, is necessarily Einstein.

Experimental and Numerical Simulation of Solar Still for the Production of Drinking Water in Desert Areas of Southern Algeria

Mekki Zerouali,Fouad Khaldi,Zina Belkhiri 대한설비공학회 2018 International Journal Of Air-Conditioning and Refr Vol.26 No.3

Solar distillation is a simple method used for the production of drinking water from saline or brackish water. This method proposes a solution for the production of fresh water in arid and desert areas, where a large solar field is available and also the existence of underground sources of saline water. A solar distiller with a single basin and double slopes is theoretically examined. The theoretical model is based on the resolution of equations of heat and mass transfer dependent on time for glazing cover, water film and absorber basin. For validating the results of the theoretical model, a comparison with the experimental results was carried out. A series of experimental tests on a solar distiller with double slopes in the climatic conditions of Ouargla in Algeria were performed. The tests were carried out on 19th February 2009. The amount of water distilled was 2.7 liters, after a day's work. The results show that the cooling of the glazing cover leads to increase in the amount of distilled water of about 17% in comparison with the reference case. In addition, we found a good agreement between the results of the theoretical model and the experimental data.

Liberalization, Regulatory Delays and Vulnerability to Systemic Banking Crisis

Mekki Hamdaoui 한국국제경제학회 2017 International Economic Journal Vol.31 No.4

This work aims at contributing to the improvement of the early warning systems of banking crises using a new approach accounting for model uncertainty. We show that a multinomial logit model based on Bayesian model averaging (BMA) is a good strategy to predict banking crisis. To do this, we argue that differences in vulnerability to banking crisis can be largely explained by an asymmetry between financial market evolution and regulation update on a sample of 49 developed and developing countries between 1980 and 2010. When markets are liberalized, competition pushes bankers to take more risks and take advantage of regulatory delays thus increasing crises probabilities. Our empirical evidence supports that crisis probability is higher in country liberalizing their banking system when regulation is not updated. We developed an early warning system for systemic banking crises based on the multinomial logit model. Its main difference to existing prediction models and its contribution to the literature is that it is intended to identify and resolve what is called by Bussiere and Fratzscher [(2006). Towards a new early warning system of financial crises. Journal of International Money and Finance, 25(6), 953–973] as post-crisis bias in binomial models and to develop a new methodology of leading indicators selection based on BMA. Overall, our model predicts all banking crises during our sample period.

A comparative study of LPWAN technologies for large-scale IoT deployment

Kais Mekki,Eddy Bajic,Frederic Chaxel,Fernand Meyer 한국통신학회 2019 ICT Express Vol.5 No.1

By 2020, more than 50 billion devices will be connected through radio communications. In conjunction with the rapid growth of the Internet of Things (IoT) market, low power wide area networks (LPWAN) have become a popular low-rate long-range radio communication technology. Sigfox, LoRa, and NB-IoT are the three leading LPWAN technologies that compete for large-scale IoT deployment. This paper provides a comprehensive and comparative study of these technologies, which serve as efficient solutions to connect smart, autonomous, and heterogeneous devices. We show that Sigfox and LoRa are advantageous in terms of battery lifetime, capacity, and cost. Meanwhile, NB-IoT offers benefits in terms of latency and quality of service. In addition, we analyze the IoT success factors of these LPWAN technologies, and we consider application scenarios and explain which technology is the best fit for each of these scenarios.

Egypte, Afrique, Culture

( Nabil Mekky ) 서울대학교 불어문화권연구소 2007 불어문화권연구 Vol.17 No.-

Les conditions de la responsabilité contractuelle

Mustapha Mekki 한국민사법학회 2013 民事法學 Vol.65 No.-

En cette période de forte harmonisation entre les systèmes juridiques, auservice d’un « Grand » droit civil européen, le système juridique françaisfait souvent l’objet de débats en raison de sa forte singularité. Il existerait,dit-on, une french touch. Cette remarque est particulièrement vraie àl’analyse de la responsabilité contractuelle et de ses conditions. Cettesingularité des conditions de la responsabilité contractuelle du droit françaisen fait toute la force. Cette force, la responsabilité contractuelle la tient, en premier lieu, de laflexibilité de ses conditions de mise en oeuvre. Elle s’appuie sur unecertaine élasticité des contours du contrat, au sens de porosité de sescontours et de densité de son contenu. Elle s’appuie également sur uneintensité variable des obligations allant de l’obligation de moyens allégée àl’obligation de résultat renforcée en passant par diverses intensités. La force de la responsabilité contractuelle vient, en deuxième lieu, de laflexibilité de ses conditions d’exonération. Ces causes d’exonération peuventêtre prévues par les parties en accordant une place centrale à la libertécontractuelle dans le respect de la force obligatoire du contrat. Ces causespeuvent également ne pas être prévues par les parties et renvoient auxcas d’exonération totale ou partielle de responsabilité. La responsabilité contractuelle est un vrai concept. La flexibilité de sesconditions de mise en oeuvre et d’exonération justifie qu’elle coexiste avecla responsabilité extracontractuelle. Son avenir dépend cependant du maintien d’un juste équilibre. L’équation idéale serait la suivante :indemniser dans le respect raisonnable de l’attente légitime des parties etdans le respect de la force obligatoire du contrat.

Estimation of Leucine Aminopeptidase and 5-Nucleotidase Increases Alpha-Fetoprotein Sensitivity in Human Hepatocellular Carcinoma Cases

Abouzied, Mekky Mohammed,Eltahir, Heba M.,Fawzy, Michael Atef,Abdel-Hamid, Nabil Mohie,Gerges, Amany Saber,El-Ibiari, Hesham Mohmoud,Nazmy, Maiiada Hassan Asian Pacific Journal of Cancer Prevention 2015 Asian Pacific journal of cancer prevention Vol.16 No.3

Purpose: To find parameters that can increase alpha-fetoprotein (AFP) sensitivity and so help in accurate diagnosis and rapid management of hepatocullular carcinoma (HCC), as AFP has limited utility of distinguishing HCC from benign hepatic disorders for its high false-positive and false negative rates. Materials and Methods: Serum levels of AFP, 5'-nucleotidase enzyme activity (5-NU) and leucine aminopeptidase enzyme (LAP) activity were measured in 40 individuals. Results: LAP and 5'NU were elevated in HCC at p<0.001. Pearson correlation coefficients showed that changes in AFP exhibited positive correlation with both 5'-NU and LAP at (p<0.001). The complementary use of LAP only with AFP resulted in an increase in sensitivity of AFP from 75% to 90% in detecting HCC. The complementary use of both LAP and 5-NU with AFP resulted in an increased sensitivity of AFP in detecting HCC from 75% to 95%. Conclusions: LAP and 5-FU can be determined in HCC patients in combination with AFP to improve its sensitivity and decrease false negative results.

계약책임의 요건

무스타파 메키(Mustapha Mekki) 한국민사법학회 2013 民事法學 Vol.65 No.-

유럽민법이라는 “큰” 법을 위해 여러 법제도들 간의 조화를 도모하는 요즈음 프랑스의 법제도가 그 독특함으로 하여 논의의 대상이 되는 경우가 많다. 이른바 프랑스풍이라는 것이 존재하는 것 같다. 계약책임과 그 요건을 분석하여 보면 특히 그러하다. 계약책임요건의 이러한 독특함은 프랑스법의 장점이다. 첫째, 계약책임의 장점은 실행요건이 유연하다는 것이다. 계약이라는 윤곽선이 탄력적이기 때문이다. 계약이라는 그릇이 다공성(多孔性)을 가지며 그 내용이 조밀하다는 의미에서 그러하다. 계약책임의 실행요건이 유연한 이유는 채무의 강도가 다양하기 때문이기도 하다. 약화된 수단채무와 강화된 결과채무라는 양 극단 사이에는 다양한 강도를 가진 채무들이 존재한다. 둘째, 계약책임의 장점은 그 면책요건이 유연하다는 것이다. 계약당사자들은 면책원인을 약정할 수 있다. 무엇보다 계약자유를 존중하여야 하지만 이는 계약의 규범적 효력을 존중하는 가운데 이루어져야 한다. 당사자들에 의해 약정되지 않은 면책원인들에는 전부면책원인과 일부면책원인이 있다. 계약책임은 진짜 개념이다. 그 실행요건과 면책요건이 유연하기 때문에 계약외책임과 더불어 존재하는 것이다. 하지만 계약책임의 장래는 공정한 평형에 달려 있다. 이상적인 방정식은 다음과 같을 것이다 : 당사자들의 정당한 기대를 합리적으로 존중하면서도 그 기대를 계약의 규범적 효력에 비추어 조정하는 가운데 배상하는 것이다.