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Search Results: 1 - 10 of 383 matches for " Younes Boujelbene "
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The Determinants of Information Asymmetry between Managers and Investors: A Study on Panel Data
Younes Boujelbene,Lobna Besbes
IBIMA Business Review , 2012,
Abstract: Thanks to the study of 124 firms listed on the SBF 250 index, the researchers were able to identify the determinants of information asymmetry between firms' managers and investors, using panel data over the period ranging from 1999 to 2008. The results of the random effects model show that most variables are not significant. There is a problem of heteroscedasticity and a problem of autocorrelation. In this regard, the researchers have used the method of generalized least squares to overcome these problems. The results obtained, by using this method, show that the trading volume, as well as the volatility of stock returns, has a positive and significant effect on information asymmetry. The coefficient of the insiders' trading variable is high what shows the relevance of this variable in the explanation of the information asymmetry problem. However, the stock price variable has a negative effect. These results are conclusive to corroborate the thesis of variables relevance resulting from the theory of markets microstructure.
Performance of Tunisian Banks Following Transformations of Banking Activities
Bassem Salhi,Younes Boujelbene
International Journal of Business and Management , 2012, DOI: 10.5539/ijbm.v7n23p31
Abstract: This article aims to study the impact of new forms of banking intermediation on the performance of Tunisian banks. The analysis was conducted on a sample of 10 Tunisian banks for a period of analysis that spans 13 years, from 1997 until 2009. To make better use of our database, we have utilized the panel data technique. Our empirical validation shows that the context of bank intermediation is still traditional, despite the reforms of financial liberalization; they still carry the traditional business model of collecting deposits and granting loans to increase their profit margins bank.
La prévision des difficultés bancaires: application d’une approche neuronale
Zina ESSID,Manel ZRIBI,Younes BOUJELBENE
Communications of the IBIMA , 2009,
Abstract: Ce papier se propose d’appliquer l’approche neuronale dans la détection des banques en difficultés en réponse aux insuffisances des méthodes de prévision traditionnelles . Il s’agit d’utiliser un échantillon de 94 banques individuelles durant la période allant de 2002à 2006 à l’aide d’une batterie de 11 ratios financiers. Notre principal résultat est la suivante : il existe une étroite complémentarité entres les techniques traditionnelles et celles de l’intelligence artificielle
Polarized Raman Spectra of
M. Boujelbene,T. Mhiri
International Journal of Spectroscopy , 2011, DOI: 10.1155/2011/128401
Abstract: The study by spectroscopie Raman relave to compound was interpreted and attributed one being based Theory of group and by comparison with others composed. The current studies of the polarised Raman spectra of give evidence that the disorder is indeed present in the ammonium alum. This is best manifested through the appearance of surplus bands in the spectral regions of vibrations of the sulphate anion. 1. Experimental 1.1. Preparation Alum crystals were prepared by the slow evaporation of an aqueous solutions containing stoichiometric amounts of and salts. 1.2. Polarised Raman Spectra of 1.2.1. Factor Group Analysis The ammonium alum, , belongs to a family of compounds with general formula (A is a univalent metal such as Na, K, Rb, and Cs; M is a trivalent metal: Al, Ce, In, Fe, Cr, Ir etc.; X is S or Se). According to the crystallographic data [1], the ammonium alum crystallizes in the cubic structure Pa-3 (T6h), . The site symmetry of sulfate is C3, the trivalent cations occupy S6 sites, and the site symmetry of the two crystallographically distinct types of water molecules is C1. In the model the site symmetry of is S6. However, X-ray diffraction studies of ammonium alum by with C3 symmetry. Abdeen et al. [2] indicated the unusual situation of two possible orientations of the sulfate ion, and the site symmetry of is C3. Similar suggestions were deduced from neutron diffraction date by Abdeen et al. [3]. Factor group analysis using standard correlation method [4] has been carried out to determine the symmetries of the vibrations and to predict the IR and Raman active modes. Excluding the acoustic modes, 227 normal modes are predicted. These are distributed as follows: The and modes are Raman active, and Fu mode is infrared active. The Au and Eu modes exposed by Suresh et al. [5] as being IR active are really inactive. The contribution of the different groupments (SO4, NH4, and ) and the ion to the Raman active vibrations are given in Table 2. Our polarized measurements were conducted on the (001) and (111) faces of the single crystal (Figure 1). Figure 1: Photograph showing (a) face (001) and (b) face (111) things of . Analysis of the tensor components shows that, on (001) face, the Fg modes were obtained in the geometry, the geometry gives both the Ag and the Eg modes. Eg mode can be observed when the crystal is oriented as in (111) face and incident and scattered beams are perpendicular , and in polarizations parallel geometry the Ag, Eg, and Fg modes can be observed. The polarized Raman spectra recorded for these different geometries are shown in
Primary Alveolar Soft Part Sarcoma of the Scapula  [PDF]
Ghada Sahraoui, Nadia Boujelbene, Raoudha Doghri, Karima Mrad
Open Journal of Orthopedics (OJO) , 2017, DOI: 10.4236/ojo.2017.71002
Abstract: Alveolar soft-part sarcoma (ASPS) is an uncommon, aggressive soft-tissue neoplasm, occurring in less than 1% of sarcomas. It is typically found in the head and neck tissues in children or in the deep soft tissues of the lower extremities in young adults. This tumor arises primarily within the skeletal muscles or musculofascial planes. Primary involvement of bone is extremely rare. ASPS has poor prognosis with a propensity for recurrence as well as distant metastasis. In this report, we present a 25-year-old male with primary ASPS in the left scapular bone and discuss the histopathological and immunohistochemical features of this sarcoma.
A Secure DHCP Protocol to Mitigate LAN Attacks  [PDF]
Osama S. Younes
Journal of Computer and Communications (JCC) , 2016, DOI: 10.4236/jcc.2016.41005
Abstract: Network security has become more of a concern with the rapid growth and expansion of the Internet. While there are several ways to provide security in the application, transport, or network layers of a network, the data link layer (Layer 2) security has not yet been adequately addressed. Data link layer protocols used in local area networks (LANs) are not designed with security features. Dynamic host configuration protocol (DHCP) is one of the most used network protocols for host configuration that works in data link layer. DHCP is vulnerable to a number of attacks, such as the DHCP rouge server attack, DHCP starvation attack, and malicious DHCP client attack. This work introduces a new scheme called Secure DHCP (S-DHCP) to secure DHCP protocol. The proposed solution consists of two techniques. The first is the authentication and key management technique that is used for entities authentication and management of security key. It is based on using Diffie-Hellman key exchange algorithm supported by the difficulty of Elliptic Curve Discrete Logarithm Problem (ECDLP) and a strong cryptographic one-way hash function. The second technique is the message authentication technique, which uses the digital signature to authenticate the DHCP messages exchanged between the clients and server.
sl(2)-Trivial Deformations of Vect_{Pol}(R)-Modules of Symbols
Mabrouk Ben Ammar,Maha Boujelbene
Symmetry, Integrability and Geometry : Methods and Applications , 2008,
Abstract: We consider the action of Vect_{Pol}(R) by Lie derivative on the spaces of symbols of differential operators. We study the deformations of this action that become trivial once restricted to sl(2). Necessary and sufficient conditions for integrability of infinitesimal deformations are given.
Managers’ perceptions of intellectual capital: An empirical study in the Tunisian context
Mohamed Ali Boujelbene,Habib Affes
Management Science Letters , 2013, DOI: 10.5267/j.msl.2013.04.011
Abstract: The purpose of this exploratory research study is to examine the extent of recognition of the concept of intellectual capital in the Tunisian context and to identify the perceptions of managers concerning the accounting treatment and disclosure of this hidden concept. A survey questionnaire was conducted among 51 Tunisian managers. The results of this survey argue that the majority of respondents perceive the elements of intellectual capital as important value drivers for their business. This study shows that managers are aware of the shortcoming of the present accounting system and they approve previous studies that propose voluntary disclosure of information relating to intellectual capital as a solution to compensate for the loss of relevance of traditional accounting information. The present study presents a significant interest in the accounting literature and provides whether it would be appropriate for the Tunisian accounting standard setter to ask companies to disclose more intellectual capital information.
The Determinants of the Profitability of the Tunisian Deposit Banks
Nesrine Ayadi,Younès Boujelbene
IBIMA Business Review , 2012,
Abstract: Thanks to the study of twelve Tunisian deposit banks, the researchers were able to identify the influence of these determinants on the bank profitability, using a technique of panel data over the period of 1995-2005. The empirical results suggest that the bank capitalization, as well as the size, have a positive and significant effect on the bank profitability. The empirical results indicate that the variables of financial structure, the ratio of the bank assets to the GDP and that of the stock market capitalization to the banking assets have a negative and a statistically significant effect. As for the impact of the macroeconomic indicators, the researchers conclude that the variables do not have a significant effect on bank profitability. Finally, the results indicate the substitutability between banks and financial markets.
sl(2)-Trivial Deformations of Vect_{Pol}(R)-Modules of Symbols
Mabrouk Ben Ammar,Maha Boujelbene
Mathematics , 2007, DOI: 10.3842/SIGMA.2008.065
Abstract: We consider the action of Vect_{Pol}(R) by Lie derivative on the spaces of symbols of differential operators. We study the deformations of this action that become trivial once restricted to sl(2). Necessary and sufficient conditions for integrability of infinitesimal deformations are given.
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