Least squares regression with errors in both variables: case studies

Analytical curves are normally obtained from discrete data by least squares regression. The least squares regression of data involving significant error in both x and y values should not be implemented by ordinary least squares (OLS). In this work, the use of orthogonal distance regression (ODR) is discussed as an alternative approach in order to take into account the error in the x variable. Four examples are presented to illustrate deviation between the results from both regression methods. The examples studied show that, in some situations, ODR coefficients must substitute for those of OLS, and, in other situations, the difference is not significant.

Suunnitellun alas- ja ylösajon todennäköisyysperustainen riskianalyysi ydinvoimalaitokselle

Työssä tehtiin ydinvoimalaitoksen suunnitellun alas- ja ylösajon todennäköisyysperus-tainen riskianalyysi. Suunnitellun alasajon analyysi sisälsi Teollisuuden Voima Oyj:n käyttämän vanhan PRA-mallin päivityksen ja laajentamisen. Ylösajon analyysiä varten kehitettiin kokonaan uusi malli. Diplomityöselostuksen alussa on yleinen katsaus luotettavuustekniikan käsitteisiin, pe-rusperiaatteisiin ja työkaluihin. Sitten on esitelty laitostekniikkaa tärkeimpien alas- ja ylösajoihin osallistuvien järjestelmien osalta. Myös normaalit alas- ja ylösajotoimenpi-teet on kuvattu. Yleisen teoriaosuuden jälkeen on keskitytty uusien mallien muodosta-miseen. Työssä käytetyt oletukset ja arviot on esitelty perusteluineen. Uudet tapahtuma- ja vikapuut sekä niiden perusteella lasketut sydänvaurioriskit johtopäätöksineen on käy-ty läpi selostuksen lopussa. Alkutapahtumataajuuksien määrittäminen tehtiin vikapuiden avulla, joissa huomioitiin komponenttivikojen, inhimillisten virheiden ja ulkoisten tekijöiden vaikutus. Aiemmin alkutapahtumat oli määritetty pääasiassa käyttöhistorian perusteella. Uusi määrittelytapa antaa eri vikaantumistapojen välille paremman kuvan niiden keskinäisestä merkitykses-tä sekä paremman päivitettävyyden laitosmuutosten yhteydessä. Mallien avulla voidaan laskea alas- ja ylösajon merkitys kokonaissydänvauriotaajuuteen entistä yksityiskohtaisemmin. Tuloksia voidaan myös hyödyntää laitosten vikatilanteis-sa, kun vertaillaan jatketun käytön ja mahdollisten korjaustöiden vaatiman alas- ja ylösajon riskejä. Uusien mallien antamat tulokset laskivat vain hieman kokonaissydän-vauriotaajuutta, mutta merkittävästi alasajon vaikutusta siihen. Ylösajosta aiheutuva riskinlisä oli noin puolet alasajon riskistä.

Toimintaprosessin kehittäminen sairaalaympäristössä teollisuustalouden menetelmin

Työn tavoitteena on tutkia reaaliaikaisen sanelunpurun vaikuttavuutta ja kannattavuutta. Reaaliaikaisen sanelunpurun vaikuttavuuden tarkastelun pohjana käytetään teollisuustalouden puolella tunnettuja ja yrityksissä laajasti käytössä olevia ajatusmalleja, kuten Leania ja Six Sigmaa. Lean –ajattelu perustuu läpimenoajan nopeuttamiseen, hukkaa ja ei lisäarvoa luovien vaiheiden eliminoimisella. Six Sigma keskittyy taas laatuun, jolloin tuote ja palveluvirheitä karsitaan. Lisäksi teoriaosassa käsitellään palveluiden ulkoistamista, tietosuojaa ja palkkakustannusten rakennetta. Empiriaosassa kuvataan kirurgianpoliklinikan ja leikkausosaston prosesseja. Prosesseissa keskitytään nykytilan sekä reaaliaikaisen sanelunpurun vaikutuksiin. Prosessien kuvaamisella saadaan tietoa toiminnan ongelmista ja kehittämiskohteista. Henkilökunnan haastatteluin selvitettiin sanelujonon vaikutuksia sekä kokemuksia ulkoistamisesta. Kustannusanalyysin avulla selvitettiin ulkoistamisen kannattavuutta reaaliaikaisessa sanelunpurussa. Työn tuloksena saatiin vaikuttavuus tarkastelu reaaliaikaisesta sanelunpurusta sekä ulkoistamisen kannattavuudesta. Prosessien kuvaaminen osoittaa, että useissa prosessin eri vaiheissa sanelujen puuttuminen aiheuttaa kustannuksia ja vaikuttaa henkilökunnan työhön. Kustannusanalyysin pohjalta sanelunpurun ulkoistaminen todettiin kannattavaksi. Jatkossa sanelunpurun ulkoistamisessa tulee kiinnittää huomiota siihen, mitkä osat sanelunpurkuprosessista halutaan ulkoistaa. Sähköisten järjestelmien kehittyminen vaikuttaa osaltaan tähän päätökseen. Lisäksi suoritepohjaisen hinnoittelun kehittäminen on tärkeä osa sanelunpurkuprosessin tehokkuutta.

Tool-supported invariant-based programming

The development of correct programs is a core problem in computer science. Although formal verification methods for establishing correctness with mathematical rigor are available, programmers often find these difficult to put into practice. One hurdle is deriving the loop invariants and proving that the code maintains them. So called correct-by-construction methods aim to alleviate this issue by integrating verification into the programming workflow. Invariant-based programming is a practical correct-by-construction method in which the programmer first establishes the invariant structure, and then incrementally extends the program in steps of adding code and proving after each addition that the code is consistent with the invariants. In this way, the program is kept internally consistent throughout its development, and the construction of the correctness arguments (proofs) becomes an integral part of the programming workflow. A characteristic of the approach is that programs are described as invariant diagrams, a graphical notation similar to the state charts familiar to programmers. Invariant-based programming is a new method that has not been evaluated in large scale studies yet. The most important prerequisite for feasibility on a larger scale is a high degree of automation. The goal of the Socos project has been to build tools to assist the construction and verification of programs using the method. This thesis describes the implementation and evaluation of a prototype tool in the context of the Socos project. The tool supports the drawing of the diagrams, automatic derivation and discharging of verification conditions, and interactive proofs. It is used to develop programs that are correct by construction. The tool consists of a diagrammatic environment connected to a verification condition generator and an existing state-of-the-art theorem prover. Its core is a semantics for translating diagrams into verification conditions, which are sent to the underlying theorem prover. We describe a concrete method for 1) deriving sufficient conditions for total correctness of an invariant diagram; 2) sending the conditions to the theorem prover for simplification; and 3) reporting the results of the simplification to the programmer in a way that is consistent with the invariantbased programming workflow and that allows errors in the program specification to be efficiently detected. The tool uses an efficient automatic proof strategy to prove as many conditions as possible automatically and lets the remaining conditions be proved interactively. The tool is based on the verification system PVS and i uses the SMT (Satisfiability Modulo Theories) solver Yices as a catch-all decision procedure. Conditions that were not discharged automatically may be proved interactively using the PVS proof assistant. The programming workflow is very similar to the process by which a mathematical theory is developed inside a computer supported theorem prover environment such as PVS. The programmer reduces a large verification problem with the aid of the tool into a set of smaller problems (lemmas), and he can substantially improve the degree of proof automation by developing specialized background theories and proof strategies to support the specification and verification of a specific class of programs. We demonstrate this workflow by describing in detail the construction of a verified sorting algorithm. Tool-supported verification often has little to no presence in computer science (CS) curricula. Furthermore, program verification is frequently introduced as an advanced and purely theoretical topic that is not connected to the workflow taught in the early and practically oriented programming courses. Our hypothesis is that verification could be introduced early in the CS education, and that verification tools could be used in the classroom to support the teaching of formal methods. A prototype of Socos has been used in a course at Åbo Akademi University targeted at first and second year undergraduate students. We evaluate the use of Socos in the course as part of a case study carried out in 2007.

Medical students' knowledge about end-of-life decision-making

The influence of medical students' knowledge concerning end-of-life care, considering ethical theories and clinical practice, remains controversial. We aimed to investigate medical students' knowledge of bioethical concepts related to moral kinds of death (euthanasia, disthanasia, and orthothanasia) and to analyze the influence of their clinical experience on practicing such approaches in a tertiary hospital in the state of São Paulo, Brazil. We interviewed 180 medical students [distributed in Group 1 (G1) - first to third- year students, and Group 2 (G2) - fourth to sixth-year students] to evaluate the influence of the course on "medical ethics" on ethical theories and clinical practice, using a closed questionnaire. The course on "medical ethics" did not distinguish the groups (P=0.704) in relation to bioethical concepts. Neologisms such as "cacothanasia" and "idiothanasia" were incorrectly viewed as bioethical concepts by 28% of the interviewees. Moreover, 45.3% of the sample considered health care professionals incapable of managing terminally ill patients, especially G2 (29%) as compared to G1 (16.5%, P=0.031). The concept of euthanasia was accepted by 41% of sample, as compared to 98.2% for orthothanasia. Among medical students that accepted ways to abbreviate life (22.9%), 30.1% belonged to G1, and only 16.1% to G2 (P=0.049). These medical students were unfamiliar with common bioethical concepts. Moreover, they considered healthcare professionals incapable of managing terminally ill patients. The ethical ideal of the "good death" reflects better acceptance of orthothanasia by medical students, suggesting a tendency to apply it in their future clinical practice.

Russian market entry decision for an e-business company, the case Ampparit Inc.

The aim of the study was to examine foreign operation methods and suggest the entry mode for the Russian E-business market. Ampparit Inc. was chosen as a case company, as it operates in the e-commerce B2B type of the business by providing Witpik - media monitoring service. The concept of foreign operation method was clarified with a specific focus on Russian market peculiarities and E-business. The main focuses of the present work were to figure out the most applicable entry mode for the Russian market in case of e-business company and factors affecting the decision about entry, including risks, barriers and other aspects.

Communicative and Anticipatory Decision-Making Supported by Bayesian Networks

The purpose of this research is to draw up a clear construction of an anticipatory communicative decision-making process and a successful implementation of a Bayesian application that can be used as an anticipatory communicative decision-making support system. This study is a decision-oriented and constructive research project, and it includes examples of simulated situations. As a basis for further methodological discussion about different approaches to management research, in this research, a decision-oriented approach is used, which is based on mathematics and logic, and it is intended to develop problem solving methods. The approach is theoretical and characteristic of normative management science research. Also, the approach of this study is constructive. An essential part of the constructive approach is to tie the problem to its solution with theoretical knowledge. Firstly, the basic definitions and behaviours of an anticipatory management and managerial communication are provided. These descriptions include discussions of the research environment and formed management processes. These issues define and explain the background to further research. Secondly, it is processed to managerial communication and anticipatory decision-making based on preparation, problem solution, and solution search, which are also related to risk management analysis. After that, a solution to the decision-making support application is formed, using four different Bayesian methods, as follows: the Bayesian network, the influence diagram, the qualitative probabilistic network, and the time critical dynamic network. The purpose of the discussion is not to discuss different theories but to explain the theories which are being implemented. Finally, an application of Bayesian networks to the research problem is presented. The usefulness of the prepared model in examining a problem and the represented results of research is shown. The theoretical contribution includes definitions and a model of anticipatory decision-making. The main theoretical contribution of this study has been to develop a process for anticipatory decision-making that includes management with communication, problem-solving, and the improvement of knowledge. The practical contribution includes a Bayesian Decision Support Model, which is based on Bayesian influenced diagrams. The main contributions of this research are two developed processes, one for anticipatory decision-making, and the other to produce a model of a Bayesian network for anticipatory decision-making. In summary, this research contributes to decision-making support by being one of the few publicly available academic descriptions of the anticipatory decision support system, by representing a Bayesian model that is grounded on firm theoretical discussion, by publishing algorithms suitable for decision-making support, and by defining the idea of anticipatory decision-making for a parallel version. Finally, according to the results of research, an analysis of anticipatory management for planned decision-making is presented, which is based on observation of environment, analysis of weak signals, and alternatives to creative problem solving and communication.

A decision support system for cost determination in grain storage facility operations

Many research works have being carried out on analyzing grain storage facility costs; however a few of them had taken into account the analysis of factors associated to all pre-processing and storage steps. The objective of this work was to develop a decision support system for determining the grain storage facility costs and utilization fees in grain storage facilities. The data of a CONAB storage facility located in Ponta Grossa - PR, Brazil, was used as input of the system developed to analyze its specific characteristics, such as amount of product received and stored throughout the year, hourly capacity of drying, cleaning, and receiving, and dispatch. By applying the decision support system, it was observed that the reception and expedition costs were exponentially reduced as the turnover rate of the storage increased. The cleaning and drying costs increased linearly with grain initial moisture. The storage cost increased exponentially as the occupancy rate of the storage facility decreased.