scholarly journals Coupling the Kolmogorov diffusion: maximality and efficiency considerations

2016 ◽  
Vol 48 (A) ◽  
pp. 15-35
Author(s):  
Sayan Banerjee ◽  
Wilfrid S. Kendall
Keyword(s):  
Brownian Motion ◽  
Finite Number ◽  
Classical Case ◽  
Single Time ◽  
Starting Values ◽  
Negative Results ◽  
Time Integral ◽  
Maximal Coupling ◽  
Coupling Strategy

AbstractThis is a case study concerning the rate at which probabilistic coupling occurs for nilpotent diffusions. We focus on the simplest case of Kolmogorov diffusion (Brownian motion together with its time integral or, more generally, together with a finite number of iterated time integrals). We show that in this case there can be no Markovian maximal coupling. Indeed, there can be no efficient Markovian coupling strategy (efficient for all pairs of distinct starting values), where the notion of efficiency extends the terminology of Burdzy and Kendall (2000). Finally, at least in the classical case of a single time integral, it is not possible to choose a Markovian coupling that is optimal in the sense of simultaneously minimizing the probability of failing to couple by time t for all positive t. In recompense for all these negative results, we exhibit a simple efficient non-Markovian coupling strategy.

scholarly journals Geometric Brownian motion with affine drift and its time-integral

2021 ◽  
Vol 395 ◽  
pp. 125874
Author(s):  
Runhuan Feng ◽  
Pingping Jiang ◽  
Hans Volkmer
Keyword(s):  
Brownian Motion ◽  
Geometric Brownian Motion ◽  
Time Integral

On the idiomatic nature of unproductive morphology

2019 ◽  
Vol 36 ◽  
pp. 99-114
Author(s):  
Karen De Clercq ◽  
Guido Vanden Wyngaerd
Keyword(s):  
Classical Case ◽  
Gradable Adjectives ◽  
Formal Relationship ◽  
Lexical Items

Abstract We present a case study in the marking of the negative prefix in French gradable adjectives, where the productive marker iN- alternates with a number of unproductive prefixes, like dé(s)-, dis-, mal-, mé(s)-. We treat this as a classical case of allomorphy, and present an account of the distribution of these allomorphs in terms of the nanosyntactic mechanism of pointers, by which lexical items may point to other, existing, lexical items in the postsyntactic lexicon. We claim that unproductive lexical items are not directly accessible for the spellout mechanism, but only indirectly, via pointers. We show how the analysis accounts for lexicalised semantics in derivations, as well as cases where the formal relationship between derivational pairs is not concatenative, but substitutive.

scholarly journals CONDITIONAL ASIAN OPTIONS

2015 ◽  
Vol 18 (06) ◽  
pp. 1550040 ◽  
Author(s):  
RUNHUAN FENG ◽  
HANS W. VOLKMER
Keyword(s):  
Brownian Motion ◽  
Life Insurance ◽  
Analytical Approach ◽  
Cost Benefit ◽  
Occupation Time ◽  
Asian Options ◽  
Numerical Examples ◽  
Academic Literature ◽  
Time Integral ◽  
Distributional Properties

Conditional Asian options are recent market innovations, which offer cheaper and long-dated alternatives to regular Asian options. In contrast with payoffs from regular Asian options which are based on average asset prices, the payoffs from conditional Asian options are determined only by average prices above certain threshold. Due to the limited inclusion of prices, conditional Asian options further reduce the volatility in the payoffs than their regular counterparts and have been promoted in the market as viable hedging and risk management instruments for equity-linked life insurance products. There has been no previous academic literature on this subject and practitioners have only been known to price these products by simulations. We propose the first analytical approach to computing prices and deltas of conditional Asian options in comparison with regular Asian options. In the numerical examples, we put to the test some cost-benefit claims by practitioners. As a by-product, the work also presents some distributional properties of the occupation time and the time-integral of geometric Brownian motion during the occupation time.

scholarly journals A transient Cramér–Lundberg model with applications to credit risk

2021 ◽  
Vol 58 (3) ◽  
pp. 721-745
Author(s):  
Guusje Delsing ◽  
Michel Mandjes
Keyword(s):  
Brownian Motion ◽  
Asymptotic Analysis ◽  
Finite Number ◽  
Regime Switching ◽  
Ruin Probability ◽  
Simulation Approach ◽  
Multiple Dimensions ◽  
Multiple Groups ◽  
Set Up ◽  
The Individual

AbstractThis paper considers a variant of the classical Cramér–Lundberg model that is particularly appropriate in the credit context, with the distinguishing feature that it corresponds to a finite number of obligors. The focus is on computing the ruin probability, i.e. the probability that the initial reserve, increased by the interest received from the obligors and decreased by the losses due to defaults, drops below zero. As well as an exact analysis (in terms of transforms) of this ruin probability, an asymptotic analysis is performed, including an efficient importance-sampling-based simulation approach.The base model is extended in multiple dimensions: (i) we consider a model in which there may, in addition, be losses that do not correspond to defaults, (ii) then we analyze a model in which the individual obligors are coupled via a regime switching mechanism, (iii) then we extend the model so that between the losses the reserve process behaves as a Brownian motion rather than a deterministic drift, and (iv) we finally consider a set-up with multiple groups of statistically identical obligors.

scholarly journals Evolutionary dataset optimisation: learning algorithm quality through evolution

2019 ◽  
Vol 50 (4) ◽  
pp. 1172-1191 ◽  
Author(s):  
Henry Wilde ◽  
Vincent Knight ◽  
Jonathan Gillard
Keyword(s):  
Finite Number ◽  
Open Source ◽  
Learning Algorithm ◽  
Clustering Algorithms ◽  
Genetic Evolution ◽  
Artificial Data ◽  
New Approach ◽  
Benchmark Datasets ◽  
Novel Method

AbstractIn this paper we propose a novel method for learning how algorithms perform. Classically, algorithms are compared on a finite number of existing (or newly simulated) benchmark datasets based on some fixed metrics. The algorithm(s) with the smallest value of this metric are chosen to be the ‘best performing’. We offer a new approach to flip this paradigm. We instead aim to gain a richer picture of the performance of an algorithm by generating artificial data through genetic evolution, the purpose of which is to create populations of datasets for which a particular algorithm performs well on a given metric. These datasets can be studied so as to learn what attributes lead to a particular progression of a given algorithm. Following a detailed description of the algorithm as well as a brief description of an open source implementation, a case study in clustering is presented. This case study demonstrates the performance and nuances of the method which we call Evolutionary Dataset Optimisation. In this study, a number of known properties about preferable datasets for the clustering algorithms known as k-means and DBSCAN are realised in the generated datasets.

What does social media have to do with health? A case study of Bangkok youths

2018 ◽  
Vol 0 (0) ◽  
Author(s):  
Chulanee Thianthai
Keyword(s):  
Social Media ◽  
Health Impact ◽  
Negative Effects ◽  
Cultural Variations ◽  
Media Usage ◽  
Negative Results ◽  
Self Development ◽  
And Gender ◽  
Depth Interviews

Abstract Objective This qualitative research aims to understand how Bangkok youths perceive social media usage effects on their physical, psychological, social and spiritual health. Methods A total of 74 Bangkok youths, aged 15–24 years old, divided according to each age and gender group participated in in-depth interviews and mobile phone search observations. Health impact was categorized into the four health aspects through content analysis according to sociological perspectives. Results Bangkok youths view social media to have both positive and negative effects on their health. Increased awareness of negative results was shown with increased age. While younger youths use social media for entertainment, older youths also use social media for self-development. Interests and degree of sensitivity varied among the genders. Conclusion Effective health education can only be achieved through future youth-centered research on social media usage based on age, gender and cultural variations.

scholarly journals Multifocal recurrence of medulloblastoma: a long follow-up case study

2020 ◽  
Vol 29 (1) ◽  
pp. 93-9
Author(s):  
Benny Zulkarnaien ◽  
Edwin Suharlim ◽  
Eka Susanto ◽  
Soehartati Argadikoesoema Gondhowiardjo
Keyword(s):  
Immunohistochemical Staining ◽  
Pediatric Patients ◽  
Proliferation Index ◽  
Ki 67 ◽  
Negative Results ◽  
Axial Mass ◽  
Positive Results ◽  
Multifocal Recurrence

Medulloblastoma is the most common malignant brain tumor in pediatric patients. Leptomeningeal dissemination often occurs in the spinal canal and rarely into the supratentorial as an extra-axial lesion. This study followed an 8-year progression of multifocal medulloblastoma recurrence as supratentorial metastasis that mimics an intra-axial mass of the temporal lobe. Pathologic examination of the temporal mass showed densely packed small round blue cells that are distributed in a ribboning pattern with areas of necrosis, rosette formation, and mitosis. Ki-67 immunohistochemical staining of the tumor showed a high proliferation index of 40% and revealed positive results for synaptophysin and negative results for glial fibrillary acidic protein and β-catenin. A long follow-up is essential to diagnose the recurrence and elucidate the progression of medulloblastoma.

scholarly journals Immigration of physicians to Slovakia – case study

2019 ◽  
Vol 17 (4) ◽  
pp. 262-273 ◽  
Author(s):  
Magdaléna Tupá ◽  
Karol Krajčo
Keyword(s):  
Health Care ◽  
Slovak Republic ◽  
State Level ◽  
The State ◽  
Avoidable Mortality ◽  
Negative Results ◽  
Lack Of Physicians ◽  
Market Situation ◽  
Foreign Doctors

The lack of physicians is a serious problem in the Slovak Republic (SR More than 5,000 physicians will be missing in the health care system in the next two years. From the report on health care status in Slovakia, according to OECD (2017), the state of health care in the country achieves very negative results in the indicators related to the human and financial resources of the monitored sector (mortality of newborns, preventable and avoidable mortality, urgent traffic, and others). The study was based on the analysis of the labor market situation in the health care sector for the profession of physician in the SR to identify the state and future need of physicians working in Slovakia, find possible solutions to the identified situation and determine which pull and push factors are the most important. The contribution of the study will be based on the analysis to suggest the ways to facilitate the employment of foreign doctors in Slovakia. The problem of the lack of specialists was considered in two directions of solving it on account of the flow of specialists from other countries: stimulation in order for the foreign medical students to stay in the country after their studies; engagement of foreign qualified doctors. Real situation with doctor stuffing in the Slovak Republic was evaluated, the forecasts until 2022 were made, the proposals on improving the management in solving this problem at the state level were made.

MODEL PEMBELAJARAN ANTAR-LEVEL PADA CREDIT UNION BEREROD GRATIA

2018 ◽  
Vol 14 (2) ◽  
Author(s):  
Wilfridus B. Elu
Keyword(s):  
Corporate Governance ◽  
Organizational Learning ◽  
Learning Process ◽  
Dynamic Balance ◽  
Credit Union ◽  
Strategic Renewal ◽  
Head Office ◽  
Negative Results ◽  
Innovation And Change

This case study is intended to describe the inter-level learning process at the Bererod Gratia Credit Union (CUBG) Jakarta and its characteristics based on the concept of inter-level learning in the organization and oriented to the strategic renewal developed by Crossan, Lane, and White (1999), which are learning between individual, group, and organizational levels through 4I: Intuiting, Interpreting, Integrating, Institutionalizing. Also described are the implications of organizational learning on corporate governance. The study was conducted on learning in solving problems of negative results case in the Bintaro Service Place (TP) and loan decisions that must involve the Head Office. Key informants consist of credit staff, Head of Office, and Committee members at Bintaro TP and General Manager at Head Office. The results show that the inter-level learning process in CUBG has a dynamic balance between learning for innovation and change (exploration) with learning for standardization for management certainty (exploitation). Learning is also holistic and includes single-loop learning to triple-loop learning. One important implication of corporate governance is the increasingly entrenched culture of check and balances at various levels of the organization. Communication centrality in learning requires the development of generative change capabilities at every level of the organization to ensure the continuity of transformation is in balance with the development of governance to maintain organizational integrity.Keywords: Organizational Learning; Inter-level Learning, Corporate Governance

Sign in / Sign up

Export Citation Format

Share Document