Η εξέλιξη των επιχειρήσεων και η ανάπτυξή τους έχει απασχολήσει από παλιά την ακαδημαϊκή κοινότητα (Gibrat 1931). Ένα εξιδεικευμένο τμήμα της βιβλιογραφίας αυτής ασχολείται με τον προσδιορισμό των παραγόντων επιβίωσης των επιχειρήσεων, που αποτελεί αντικείμενο της παρούσας διατριβής. Οι παράγοντες αυτοί μπορεί να αναφέρονται σε ίδια χαρακτηριστικά των επιχειρήσεων και του κλάδου στον οποίο ανήκουν ή και σε μακροοικονομικούς παράγοντες. Ο προαναφερθείς σκοπός επιτυγχάνεται μέσα από την ανάπτυξη των θεωρητικών υποθέσεων με βάση τις οποίες καταρτίζεται το οικονομετρικό υπόδειγμα. Το κύριο βάρος της εργασίας εστιάζεται στην ανάλυση των συνεχών υποδειγμάτων κινδύνου και το έλεγχο των υποθέσεων στα οποία βασίζονται. Ειδικότερα εξετάζεται η επίδραση της μορφής των δεδομένων και της χρονικής συνάθροισης στους εκτιμητές των εφαρμοζόμενων στην μέχρι σήμερα εμπειρική έρευνα υποδειγμάτων. Συγκρίνοντας διαφόρους τύπους διακριτών και συνεχών υποδειγμάτων κινδύνου οδηγούμεθα στο συμπέρασμα ότι τα μέχρι σήμερα εφαρμοζόμενα συνεχή υποδείγματα καταλήγουν σε μεροληπτικά αποτελέσματα. Η εφαρμογή διακριτών υποδειγμάτων κινδύνου PCE, που αποτελεί και την συνεισφορά μας στη βιβλιογραφία, περιορίζει σε σημαντικό βαθμό τα μειονεκτήματα των εφαρμοζόμενων στην εμπειρική έρευνα υποδειγμάτων. Η εφαρμογή της παραπάνω μεθοδολογίας προϋποθέτει δεδομένα τύπου longitudinal τα οποία δεν είναι συνήθως διαθέσιμα. Αυτό εξηγεί το γεγονός των περιορισμένων εμπειρικών εργασιών στο χώρο της επιβίωσης των επιχειρήσεων. Δεδομένης της δυσκολίας εξεύρεσης κατάλληλων δεδομένων η εμπειρική εφαρμογή στηρίχθηκε σε δεδομένα δημοσίων εγγραφών της ελληνικής κεφαλαιαγοράς για την περίοδο 1993-2002. Από όσο είμαστε σε θέση να γνωρίζουμε είναι η πρώτη φορά στη βιβλιογραφία που διεξάγεται παρόμοια έρευνα με ελληνικά δεδομένα δημοσίων εγγραφών. Τέλος, η διατριβή καταλήγει στην εξαγωγή των βασικών συμπερασμάτων και προτάσεων σχετικά με μελλοντική έρευνα. / Most economic phenomena are measured over long time intervals and this naturally leads us to see time as a discrete variable. More precisely, the underlying duration process occurs in continuous time, while the observed data comes in grouped form. In applied research, while firm life data are grouped into time intervals, continuous hazard models are used. The purpose of this paper is to investigate the sensitivity of regression coefficients and the coefficient duration dependence of the discrepancy between the statistical model and the data generating process.

Vi har studerat arbetsgivarinträdets (1992) och medfinansieringsansvarets (2005) påverkan på sjukfrånvaron i Sverige. För att göra detta har vi använt oss av sjukfrånvarostatistik från Svenskt Näringsliv ”Tidsanvändningsstatistik” vilket är genomsnittstal baserat på ungefär 210 000 arbetstagare. På detta material har vi skattat regressionsmodeller för kort och lång sjukfrånvaro samt med och utan arbetslöshet, som är tänkt att fungera som indikator för konjunkturläget, vilken i Sverige tycks påverka sjukskrivningstalen. Vi får fram att arbetsgivarinträdet verkar ha minskat de korta sjukskrivningarna samtidigt som arbetslösheten i samtliga fall är en signifikant förklarande del i sjukfrånvaron. Vi ser å andra sidan tecken på att arbetsgivarinträdet 1992 kan ha förlängt frånvarotiden hos de långtidssjukskrivna. Medfinansieringsansvaret tycks ha minskat sjukskrivningarna på både kort- och långtidsfrånvaron.

I denna uppsats undersöks hur moral hazard påverkas i grupplån vid frånvaro av sociala band, övervakning, och kontinuerliga krediter. Undersökningen förklarar grupplån i teori men presenterar även empiriskt material från andra författares artiklar. Undersökningen visar att de sociala banden inte har den avgörande betydelsen som teorin förutsätter. Vidare konstateras att nära övervakning och låntagarens behov av framtida lån har stor betydelse för att reducera moral hazard.

Syftet med den här uppsatsen är att klargöra hur omvärlden hanterar det skuldproblem som blir allt mer omfattande i många utvecklingsländer. Många afrikanska länder söder om Sahara har fastnat i en fattigdomsfälla och är i desperat behov av förändring. Det globala finansiella systemet, med IMF i spetsen, har uppmärksammat detta problem och genom omstruktureringar och avskrivningar av skulderna vill de ge länderna en möjlighet att komma på fötter igen. Många svårigheter uppkommer när externa parter kommer in och ska lösa skuldproblemen åt länderna. Hänsyn måste tas till de som har givit lånen, såväl som till de skuldsatta ländernas ekonomiska struktur. Min frågeställning i denna uppsats rör hur det finansiella systemet hanterar skuldkrisen och om det skulle kunna finnas bättre alternativ till de processer som används idag. Genom min avhandling kom jag fram till att det kommer att krävas att en extern part är närvarande i förhandlingarna mellan långivare och låntagare för att undvika obalans och orättvisa. Det som framförallt måste ändras är dock att göra de huvudsakliga aktörerna, långivarna och låntagarna, mer delaktiga i processerna för att bättre resultat ska uppnås.

This thesis reports a rock slope hazard investigation located in the Central Andes of Chile, where two significant rock mass wasting events were recognized. Dating using cosmogenic nuclide for ³⁶Cl showed that the deposits were post-glacial in age, corresponding to the Upper Pleistocene Portillo Rock Avalanche (PRA) and a Holocene rock slump and rockslide. The pre-historic landslide deposits underlie both a key transportation route between Chile and Argentina and an important ski resort. The purpose of this research was to investigate the likely failure mechanism and characterise the runout path and volume of the PRA. The insights gained on the back analysis of the slope were used in later stages to assess the hazard potential of a recurring major rockslide. The distinct element code UDEC was used to evaluate the failure mechanism. Elasto-plastic modelling results showed that sliding and shearing along the bedding planes together with brittle fracturing and shearing through the toe of the slope likely had occurred. Runout simulations were carried out using DAN3D. Combinations of rheologies were tested and ranked based on their ability to represent the current distribution of the debris by means of pre-failure topography reconstruction and volume estimates of the deposits. Results showed that the best basal rheological combination for the PRA was frictional during the rockslide and Voellmy when entrainment became important. In contrast, a constant frictional basal rheology best represented the Holocene rock slump. The performance of the present-day state of the slope was tested under different scenarios. Under static condition the slope proved to be stable indicating a stabilized geometrical profile with time. Also, the slope proved to be stable under increased pore water pressures at its toe. Finally the modelled slope was subjected to a seismic load (M=7.8) and its crest failed due to an outward rotation of blocks, probably aided by topographic amplification. The runout simulations showed that the leading edge of the flow could override part of the International Santiago-Mendoza Corridor with no direct impact to the Portillo Ski Resort. Overall, though, under this highly unlikely dynamic condition for the site, the hazard level is very low.

In biomedical research and lifetime data analysis, the comparison of two hazard functions usually plays an important role in practice. In this thesis, we consider the standard independent two-sample framework under right censoring. We construct efficient and useful confidence intervals for the ratio and difference of two hazard functions using smoothed empirical likelihood methods. The empirical log-likelihood ratio is derived and its asymptotic distribution is a chi-squared distribution. Furthermore, the proposed method can be applied to medical diagnosis research. Simulation studies show that the proposed EL confidence intervals have better performance in terms of coverage accuracy and average length than the traditional normal approximation method. Finally, our methods are illustrated with real clinical trial data. It is concluded that the empirical likelihood methods provide better inferential outcomes.

Neonatal Intensive Care Unit (NICU) patients present unique patient identification challenges. Prospective hazard analysis (PHA) assesses safety by identifying hazards before an adverse event occurs. This project analyzes a barcoded feeding process in one NICU, and conducts a preliminary evaluation of PHA methods. Observations were conducted to quantify patient identification methods used in one NICU; the unit’s barcoded feeding process was examined for potential failures. The process underwent PHA with two methods, Global Hazard Ratings (GHR), a simplified method developed for this project, and Failure Modes and Effects Analysis (FMEA). FMEA showed greater interrater reliability; there was poor agreement between methods. A list of 21 hazards was developed for the clinical team from the FMEA results. Recommendations are for the unit to formulate and implement mitigation strategies for the identified hazards. Future work involves a more in depth look at FMEA interrater reliability and reliability comparison with other PHA methods.

No description available.

Risks posed by geohazards to urban centres are constantly increasing, due to the continuous increase in population and associated infrastructure. A major risk to North Island urban centres is impacts from volcanic ashfall. This study analyses the vulnerabilities of selected New Zealand lifelines infrastructure to volcanic ash, to better understand and mitigate these risks. Telecommunications and wastewater networks are assessed, as is the vulnerability of Auckland Airport and grounded aircraft. The ability of vehicles to drive on ash covered roads is also tested, to determine the extent to which emergency services, utility providers and the public will be able to travel during and immediately after ashfall. Finally, air-conditioners have been identified as a significant vulnerability during ashfall, due to the high dependence on cooling for infrastructure and lifelines providers. These are examined to quantify the effects of ashfall on their performance. Each of the selected infrastructure types is assessed through a review of past impacts of ashfall, and experimentation either in the field or under laboratory conditions. Where appropriate, mitigation options that reduce identified vulnerabilities are considered. In most cases these options are operational rather than physical engineering solutions, and indicate pre-planning and response requirements. Key recommended mitigation options include the acquirement or strategic relocation of resources prior to ashfall, regular cleaning and maintenance of essential air conditioners during ashfall to enable their continued use, access to appropriate vehicles for utility providers to reach infrastructure, and discharge of untreated wastewater into Waitemata harbour at Orakei during ashfall on Auckland, to preserve the ability to continue treating wastewater at the Mangere treatment plant

Explosive volcanic eruptions frequently expel ballistic projectiles, producing a significant proximal hazard to people, buildings, infrastructure and the environment from their high kinetic and thermal energies. Ballistic hazard assessments are undertaken as a risk mitigation measure, to determine probabilities of eruptions occurring that may produce ballistics, identify areas and elements likely to be impacted by ballistics, and the potential vulnerabilities of elements to ballistics. The 6 August, 2012 hydrothermal eruption of Upper Te Maari Crater, Tongariro, New Zealand ejected blocks over a 6 km2 area, impacting ~2.6 km of the Tongariro Alpine Crossing (TAC), a walking track hiked by ~80,000 people a year, and damaging an overnight hut along the track. In this thesis ballistic hazard and risk from Upper Te Maari Crater are assessed through a review of its eruptive history, field and orthophoto mapping of the 6 August ballistic impact distribution, forward modelling and analysis of possible future eruption scenarios using a calibrated 3D ballistic trajectory model, and analysis of the vulnerability of hikers along the impacted Tongariro Alpine Crossing. Orthophoto mapping of the 6 August ballistic impact crater distribution revealed 3,587 impact craters with a mean diameter of 2.4 m. However, field mapping of accessible regions indicated an average of at least four times more observable impact craters and a smaller mean crater diameter of 1.2 m. By combining the orthophoto and ground-truthed impact frequency and size distribution data, it is estimated that approximately 13,200 ballistic projectiles were generated during the eruption. Ballistic impact distribution was used to calibrate a 3D ballistic trajectory model for the 6 August eruption. The 3D ballistic trajectory model and a series of inverse models were used to constrain the eruption directions, angles and velocities. When combined with eruption observations and geophysical observations and compared to the mapped distribution, the model indicated that the blocks were ejected in five variously directed eruption pulses, in total lasting 19 seconds. The model successfully reproduced the mapped impact distribution using a mean initial particle velocity of 200 m/s with an accompanying average gas flow velocity over a 400 m radius of 150 m/s. Assessment of the vulnerability of hikers to ballistics from the August eruption along the TAC utilised the modelled spatial density of impacts and an assumption that an average ballistic impact will cause serious injury or death (casualty) over an 8 m2 area. It is estimated that the probability of casualty ranged from 1% to 16% along the affected track (assuming an eruption during the time of exposure). Future ballistic hazard and vulnerability along the TAC are also assessed through application of the calibrated model. A magnitude larger eruption (than the 6 August) in which 10x more particles were ejected, doubled the affected length of the TAC and illustrated that the probability of casualty could reach 100% in localised areas of the track. In contrast, ballistics ejected from a smaller eruption did not reach the track as was the case with the 21 November 2012 eruption. The calibrated ballistic model can therefore be used to improve management of ballistic hazards both at Tongariro and also, once recalibrated, to other volcanoes worldwide.