Boundary crossing problems in insurance

University of Technology, Sydney. Faculty of Science.In the actuarial sense, a risk process models a surplus of an insurance company. The company is allowed to invest money with a constant interest rate. Some generalizations of the constant interest rate models are also considered. Ruin is defined to have occurred when the risk process reaches some certain level, which is less than the initial capital. In particular the level is assumed to be zero. Papers such as Harrison [17], Schmidli [37] and Embrechts & Schmidli [11] consider similar models with constant interest rate and obtain explicit solutions as well as diffusion approximations for the probability of ruin in infinite time. Our main approach is to use Martingale techniques in order to obtain exact solutions for probabilities of ruin in the finite time horizon which are further compared with numerical simulations. Furthermore, we analyse models with more general interest rate and propose a series of methods which can be used in order to determine the finite time ruin probabilities

Bite force and its correlation with long face in children and youth

Background: Bite force is one of the indicators of proper functioning of the stomatognathic system, and its value may have diagnostic significance in disorders of the musculoskeletal system of facial bones. The aim of the study was to evaluate the relationship between gender and age, and bite force in patients with high­-angle vertical relationship of jaws and cranial bases. Materials and methods: The study group comprised 66 subjects aged 7–17 years, in whom the mandibular jaw base line and maxillary jaw-base line (ML-NL) angles were greater than 27° and the mandibular jaw-baseline and the anterior cranial base line (ML-NSL) above 33°, and a control group (n = 54) aged 7–16 years, in which the ML-NL angles were 20.0 ± 7.0° and ML-NSL 28.0 ± 5.0°. For measuring the bite force, a Japanese digital dynamometer Imada type ZPS-LM­-2000N was used. Results: In the study group no statistically significant correlation between the bite force and gender was shown, and in the control group the average bite force on the right side was significantly different for boys and girls, whereas for boys it was higher. In the study group the relationship between the age and average and maximum bite force on the right and left side was significant. In the group of people with a high-angle relationship of bases of jaws and skull no statistically significant correlation between the bite force and gender was shown. Conclusions: The was no effect of gender on the bite force in all subjects up to 18 years of age, both in patients with a high-angle and normal relationship of bases of jaws and skull. In people with a high-angle relationship of bases of jaws and cranium masticatory forces increase with age

The relationship between selected parameters of a cephalometric analysis determining the vertical morphology of facial skeleton and bite force

Background: There are few studies devoted to an assessment of the relation between bite force and detailed results of cephalometric analysis that determine craniofacial structure. The purpose of the study was to assess the correlation between the selected criteria determining the craniofacial structure and bite force in patients with normal and increased vertical relation of the bases of jaws and skull. Materials and methods: The study material included 120 patients, aged between 7 and 17 years, who presented for examination and possible orthodontic treatment. The patients were divided into a study group and a control group. The basis of this division were ML-NL and ML-NSL angles, according to Segner’s and Hasund’s analysis standards, respectively: above 27° and above 30° in the study group, and 20.0 ± 7.0° and 28.0 ± 5.0° in the control group. Bite force was tested using a digital dynamometer calibrated in Newtons. The measurement was performed at the level of the first permanent molars. Vertical relations were assessed using the following cephalometric measurements: ML-NSL, ML-NL, NL-NSL, N-Me, Sp-Me, SpMe:NMe, ms-NL, SGo:NMe. Results: Bite force was not found to be dependent on the lower anterior face height (Sp-Me), the ratio of anterior lower to total anterior face height (SpMe:NMe), and NL-NSL angle both in patients with abnormal and normal relations of bases of jaws and skull. Although statistically non-significant, the average mean and maximum bite force values were found to be lower in patients with high-angle relation of bases of jaws and skull than in subjects with normal relation of bases of jaws and skull. Conclusions: Among the selected parameters determining the vertical craniofacial structure, the rear height of the alveolar process (ms-NL) exerts the greatest influence on bite force in both patients with increased and normal vertical relation of bases of jaws and skull, and with an increase in the value of ms-NL, bite force is reduced.

The influence of insulation of walls of industrial objects on thermal regime at the heating system of gas infrared radiators

The results of a numerical study of the process of heat transfer from the gas infrared emitters in the heated accommodation are represented. Simulation was conducted taking into account the heat withdrawal in the enclosing constructions and of heat exchange with the environment. The estimation of the average values of temperatures of air indoors in the dependence on the different intensity of heat withdrawal into the vertical walls is carried out (when the layer of insulation is present, and without it)

Guanxi – chińska sieć wzajemnych powiązań (komunikat)

Guanxi – Chinese Network of Interrelationships (communique)The meaning and the role of the network and guanxi are similar. The difference lies in the basis for the connections and methods used to make a long-term relationship with members of the network. The example can be Western instrumental network which is not equal with the social network. In Chinese culture, both are identical. In Western culture the relationship grows out of deals, but in China it is different, and deals grow out of the relationship. Westerners are generally unaware of the fact that in China social relationships are more meaningful than in the West. They are fundamental to the Chinese national character. In the West one does not need to have a personal relationship with members of the instrumental network

The APS Control System Network Upgrade

When it was installed,the Advanced Photon Source (APS) control system network was at the state-of-the-art. Different aspects of the system have been reported at previous meetings [1,2]. As loads on the controls network have increased due to newer and faster workstations and front-end computers, we have found performance of the system declining and have implemented an upgraded network. There have been dramatic advances in networking hardware in the last several years. The upgraded APS controls network replaces the original FDDI backbone and shared Ethernet hubs with redundant gigabit uplinks and fully switched 10/100 Ethernet switches with backplane fabrics in excess of 20 Gbits/s (Gbps). The central collapsed backbone FDDI concentrator has been replaced with a Gigabit Ethernet switch with greater than 30 Gbps backplane fabric. Full redundancy of the system has been maintained. This paper will discuss this upgrade and include performance data and performance comparisons with the original network

A novel approach for cross-selling insurance products using positive unlabelled learning

Successful cross-selling of products is a key goal of companies operating within the insurance industry. Choosing the right customer to approach for cross-purchase opportunities has a direct effect on both decreasing customer churn rate and increasing revenue. Unlike sales data of general products, insurance sales data typically contains only a few products (e.g., private medical insurance, life insurance, etc), it is highly imbalanced with a vast majority of customers with no cross-purchasing information, highly noisy due to varying purchase behaviour between different customers, and has no ground truth for knowing if the majority customers are truly non-cross-sell customers or they are missed opportunities. These data challenges render the building of machine learning models for accurately identifying potential cross-sell customers extremely difficult. This paper proposes a novel approach to solve this challenging problem of cross-sell customer identification using Positive Unlabelled (PU) learning in conjunction with advanced feature engineering on customer demographic data and unstructured customer question-response texts through topic modelling. We implement a bagging approach to iteratively learn the positive samples (the confirmed cross-sells) alongside random sub-samples of the unlabelled set. The proposed approach is extensively evaluated on real insurance data that has been newly collected from a leading insurance company for this study. Evaluation results demonstrate that our approach can successfully identify new potential opportunities for likely cross-sell customers