33 research outputs found
FONDEMENTS THEORIQUES ET TRAVAUX EMPRIQUES RELATIFS AU CONCEPT DE LA DEFAILLANCE DES ENTREPRISES
No full textLe cadre théorique est une composante primordiale au niveau des travaux de recherche, l’objectif principal est la présentation d’une revue de littérature qui valorise les différentes théories. Dans cet article, nous avons essayée de présenter les fondements théoriques de la défaillance des entreprises qui mettent en valeur les avancées de plusieurs penseurs, chercheurs et économistes au niveau de la théorie classique, la théorie néoclassique, les nouvelles théories notamment les théories contractuelles, la théorie des coûts de transaction, la théorie de l’agence et la théorie de la nouvelle économie. D’autant plus, le concept de la défaillance est traité selon l’approche économique et financière afin d’énumérer les travaux empiriques menés par des praticiens
LE FINANCEMENT PARTICIPATIF: ENJEUX ET PERSPECTIVES DE DEVELOPPEMENT AU MAROC
No full textDepuis ces dernières années, le mot « Crowdfunding » est présent dans les médias et dans plusieurs réseaux sociaux, il s’impose progressivement comme une nouvelle source de financement crédible pour des porteurs de projets impatients de faire vivre leurs idées. C’est un mécanisme de levée de fonds, qui repose sur le recours à une communauté pour financer le développement d’un projet et qui vise notamment à démocratiser l’accès au financement de l’économie pour les particuliers. Il représente ainsi l’une des rares alternatives aux circuits de financement traditionnels. Au Maroc, ce mode de financement est en cours d’évolution et les plateformes opérant dans ce mode sont très petites. Bien que ce mécanisme alternatif soit de plus en plus connu au sein de l’économie marocaine, plusieurs freins entravent son expansion au Maroc (absence de textes réglementaires, nouveauté du concept, manque d’expériences marocaines dans les plateformes étrangères…). L’objectif de ce papier est d’analyser les enjeux et les perspectives de développement du Crowdfunding au Maroc.
 
Spécificités théoriques des PME marocaines et profil des entreprises défaillantes
No full textLa petite et moyenne entreprise était depuis toujours le centre des préoccupations des chercheurs économistes, sauf qu’il existe toujours une ambivalence dans sa détermination vu le niveau de maturité et le cadre économique et juridique de chaque pays. Dans un contexte économique caractérisé par une forte présence des petites et moyennes entreprises accompagné par une concurrence rude et acharnée, plusieurs entreprises se trouvent dans l’incapacité de continuer leurs activités à cause d’un certain nombre de difficultés économiques et financières qui mènent vers la défaillance. En règle générale, ces entraves ne se manifestent pas brusquement, en effet, avant que l’entreprise soit considérée comme défaillante, elle doit agir face à ses difficultés.
L’objectif de cet article est de révéler les spécificités théoriques des PME marocaines et les caractéristiques qui forment le profil des entreprises défaillantes
Financial and economic determinants of business failure : Review of the literature
No full textRésumé :
Dans un contexte économique caractérisé par une forte présence des petites et moyennes entreprises, plusieurs entreprises se trouvent dans l’incapacité de continuer leurs activités à cause d’un certain nombre de difficultés économiques et financières qui mènent vers la défaillance.
La détermination des principaux facteurs explicatifs de la défaillance est une tâche très complexe pour la simple raison que ces facteurs sont multiples et peuvent être endogènes ou exogènes. Les causes de la défaillance sont multiples mais leurs conséquences impactent négativement la survie de l’entreprise.
Le présent article s’inscrit dans le cadre théorique de la défaillance, il a pour objectif principal de définir les facteurs financiers et économiques déterminants de la défaillance selon les différentes pensées économiques.
Mots clés : Défaillance des entreprises, facteurs financiers et économiques, pensées économiques.Résumé :
Dans un contexte économique caractérisé par une forte présence des petites et moyennes entreprises, plusieurs entreprises se trouvent dans l’incapacité de continuer leurs activités à cause d’un certain nombre de difficultés économiques et financières qui mènent vers la défaillance.
La détermination des principaux facteurs explicatifs de la défaillance est une tâche très complexe pour la simple raison que ces facteurs sont multiples et peuvent être endogènes ou exogènes. Les causes de la défaillance sont multiples mais leurs conséquences impactent négativement la survie de l’entreprise.
Le présent article s’inscrit dans le cadre théorique de la défaillance, il a pour objectif principal de définir les facteurs financiers et économiques déterminants de la défaillance selon les différentes pensées économiques.
Mots clés : Défaillance des entreprises, facteurs financiers et économiques, pensées économiques
Fig. 3 in Equus kiang (Perissodactyla: Equidae)
No full textFig. 3.—Geographic distribution of Equus kiang. The bold line delineates the species distribution. The distribution areas of the proposed subspecies are indicated as follows: 1, E. k. holdereri; 2, E. k. kiang; 3, E. k. polyodon;? 5 uncertain subspecies identification (modified from Schaller 1998 and used with permission of the author).Published as part of Mardini, Mamoun T, Bai, Chen, Wanigatunga, Amal A, Saldana, Santiago, Casanova, Ramon & Manini, Todd M, 2009, Equus kiang (Perissodactyla: Equidae), pp. 1-11 in Mammalian Species (Basel, Switzerland) 21 (10) on page 3, DOI: 10.1644/835.1, http://zenodo.org/record/503367
Beyond Labeling: Using Clustering to Build Network Behavioral Profiles of Malware Families
No full textMalware family labels are known to be inconsistent. They are also black-box since they do not represent the capabilities of malware. The current state of the art in malware capability assessment includes mostly manual approaches, which are infeasible due to the ever-increasing volume of discovered malware samples. We propose a novel unsupervised machine learning-based method called MalPaCA, which automates capability assessment by clustering the temporal behavior in malware's network traces. MalPaCA provides meaningful behavioral clusters using only 20 packet headers. Behavioral profiles are generated based on the cluster membership of malware's network traces. A Directed Acyclic Graph shows the relationship between malwares according to their overlapping behaviors. The behavioral profiles together with the DAG provide more insightful characterization of malware than current family designations. We also propose a visualization-based evaluation method for the obtained clusters to assist practitioners in understanding the clustering results. We apply MalPaCA on a financial malware dataset collected in the wild that comprises 1.1 k malware samples resulting in 3.6 M packets. Our experiments show that (i) MalPaCA successfully identifies capabilities, such as port scans and reuse of Command and Control servers; (ii) It uncovers multiple discrepancies between behavioral clusters and malware family labels; and (iii) It demonstrates the effectiveness of clustering traces using temporal features by producing an error rate of 8.3%, compared to 57.5% obtained from statistical features.Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Cyber SecurityOrganisation & Governanc
Uncertainty and Project Management in Construction Projects: Approaches used by public clients
No full textConstruction projects are filled with uncertainty. Such projects are becoming more complex: Many different interrelated aspects that are subject to change play a role in the delivery of construction work. This makes it interesting to know what exactly is uncertain in these projects, and what can be done to manage uncertainty. The aim of this research is to explore what aspects of complex construction projects are uncertain and what project management teams of public clients do to manage uncertainty before it impacts projects. Four complex construction projects were studied at two large public clients in the Netherlands: Rijksvastgoedbedrijf and Rijkswaterstaat. A total of 17 interviews were carried out across the project teams of these cases. A literature study was conducted to provide a theoretical basis of uncertainty in complex projects and approaches for the management of uncertainty. Uncertainty can be present in eight aspects: Objectives, methods, market, resources, stakeholders, contract, technology and environment. And managing uncertainty can be done in three ways: Learning, representing complexity and selectionism.The results show a variety of uncertainties present in those projects: all eight aspects were found to involve uncertainty in the cases. What especially appears as a challenge is the state of objects in renovation projects. This was a significant uncertainty that played a role in three renovation cases. Interestingly, project teams know before the start of the project that this is an uncertainty, but still face surprises during the execution phase. In addition, objectives, stakeholders and environment were uncertain in most of the cases. Given this broad spectrum of uncertainties, what do project teams do to prepare for this? Public clients mainly use approaches that represent the complexity of the project. They do this mainly by using organizational structures that focus on collaboration and integration. Organizational structures are utilized to facilitate joint risk management between the contractor and the public client. In addition, other approaches are used to represent complexity. Uncertainties are identified and discussed in a project development process to develop new project-specific knowledge. Decision-makers are often involved to increase the decision power of the project team or to escalate matters that are beyond influence of the project team. And lastly, project teams often focus on financial reserves and creating cohesion between project parties to prepare for unforeseen situations. learning is the second most used approach to prepare for uncertainty. It is mainly used in the renovation projects that were studied, where experiments at the site, use of mockups off site and pilots are introduced to learn about the interaction between the construction method, the object and the environment. The findings show that public clients manage a variety of uncertainties through the representation of complexity in the project organization and by learning. Selectionism was not used in the cases, and it is not clear to which extent selectionism is viable in complex construction projects. Based on the literature, it is recommendable for public clients to use integrated project teams to manage complex construction projects.Civil Engineering | Construction Management and Engineerin
Quantifying Location Privacy for Navigation Services in Sustainable Vehicular Networks
No full textCurrent connected and autonomous vehicles will contribute to various and green vehicular services. However, sharing personal data with untrustworthy Navigation Service Providers (NSPs) raises serious location concerns. To address this issue, many Location Privacy-Preserving Mechanisms (LPPMs) have been proposed. In addition, several quantification methods have been designed to help understand location privacy and illustrate how location privacy is leaked. However, their assessment is insufficient due to the incomplete assumptions about the adversary’s model. In particular, users tend to request the same navigation routes from home to workplace and acquire traffic information along the route. An adversary can collect the coordinates of adjacent locations and infer the two true locations. In this paper, we provide a formal framework for the analysis of LPPMs in navigation services. Our framework captures extra information that is available to an adversary performing localization attacks. By formalizing the adversary’s performance, we also propose and justify two new metrics to quantify location privacy in navigation services, namely accuracy and visibility. We assess the efficacy of two popular LPPMs for location privacy, i.e., differential privacy and k-anonymity. Experimental results demonstrate that the adversary can recover users’ locations with a high probability.Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Cyber Securit
Nereus: Anonymous and Secure Ride-Hailing Service based on Private Smart Contracts
No full textSecurity and privacy issues have become a major hindrance to the broad adoption of Ride-Hailing Services (RHSs). In this article, we introduce a new collusion attack initiated by the Ride-Hailing Service Provider (RHSP) and a driver that could easily link the real riders and their anonymous requests (credentials). Besides this attack, existing work requires heavy computations to execute user matching, and it is challenging for riders to verify matching results. Meanwhile, a malicious driver may cancel an assigned ride order due to its short distance. To address these issues, we present a RHS system named Nereus to support collusion resistance, efficiency, verifiability, and accountability. First, we integrate a smart contract into a Software Guard Extensions (SGX) enclave to establish a private smart contract for collusion resistance. We use a Bloom filter to achieve efficient matching. Second, we leverage privacy-preserving range query and Merkle proofs to make matching results verifiable. Meanwhile, we adopt short group signatures to provide anonymous authentication and deposit commitments to hold the runaway driver accountable. We formally state and prove the security and privacy of Nereus. We build a prototype based on Ethereum and SGX to conduct extensive performance analysis in regard to gas costs, computational costs, and communication overhead. Experimental results show that Nereus significantly improves over existing schemes in terms of computational costs.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Intelligent SystemsCyber Securit
User-Defined Privacy-Preserving Traffic Monitoring Against n-by-1 Jamming Attack
No full textTraffic monitoring services collect traffic reports and respond to users' traffic queries. However, the reports and queries may reveal the user's identity and location. Although different anonymization techniques have been applied to protect user privacy, a new security threat arises, namely, n-by-1 jamming attack, in which an anonymous contributing driver impersonates n drivers and uploads n normal reports by using n reporting devices. Such an attack will mislead the traffic monitoring service provider and further degrade the service quality. Existing traffic monitoring services do not support customized queries, and private information retrieval techniques cannot be applied directly in traffic monitoring. We formally define the new attack and propose a traffic monitoring scheme TraJ to defend the attack and achieve user-defined location privacy. Specifically, we bridge anonymous contributing drivers without disclosing their speed set by using private set intersection. Each RSU collects time traffic reports and structures a weighted proximity graph to filter out malicious colluding drivers. We design a user-defined privacy-preserving query method by encoding complex road network. We leverage the uploading phase from private aggregation to collect traffic conditions and allow requesting drivers to dynamically and privately query traffic conditions. We provide a formal analysis of TraJ to prove its privacy and security properties. We also construct a prototype based on a real-world dataset and Android smartphones to demonstrate its feasibility and efficiency. A formal analysis demonstrates the privacy and security properties. Extensive experiments illustrate the performance and defense efficacy.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Cyber Securit
