Formal development of resilient distributed systems

Resilience is the property of a system to remain trustworthy despite changes. Changes of a different nature, whether due to failures of system components or varying operational conditions, significantly increase the complexity of system development. Therefore, advanced development technologies are required to build robust and flexible system architectures capable of adapting to such changes. Moreover, powerful quantitative techniques are needed to assess the impact of these changes on various system characteristics. Architectural flexibility is achieved by embedding into the system design the mechanisms for identifying changes and reacting on them. Hence a resilient system should have both advanced monitoring and error detection capabilities to recognise changes as well as sophisticated reconfiguration mechanisms to adapt to them. The aim of such reconfiguration is to ensure that the system stays operational, i.e., remains capable of achieving its goals. Design, verification and assessment of the system reconfiguration mechanisms is a challenging and error prone engineering task. In this thesis, we propose and validate a formal framework for development and assessment of resilient systems. Such a framework provides us with the means to specify and verify complex component interactions, model their cooperative behaviour in achieving system goals, and analyse the chosen reconfiguration strategies. Due to the variety of properties to be analysed, such a framework should have an integrated nature. To ensure the system functional correctness, it should rely on formal modelling and verification, while, to assess the impact of changes on such properties as performance and reliability, it should be combined with quantitative analysis. To ensure scalability of the proposed framework, we choose Event-B as the basis for reasoning about functional correctness. Event-B is a statebased formal approach that promotes the correct-by-construction development paradigm and formal verification by theorem proving. Event-B has a mature industrial-strength tool support { the Rodin platform. Proof-based verification as well as the reliance on abstraction and decomposition adopted in Event-B provides the designers with a powerful support for the development of complex systems. Moreover, the top-down system development by refinement allows the developers to explicitly express and verify critical system-level properties. Besides ensuring functional correctness, to achieve resilience we also need to analyse a number of non-functional characteristics, such as reliability and performance. Therefore, in this thesis we also demonstrate how formal development in Event-B can be combined with quantitative analysis. Namely, we experiment with integration of such techniques as probabilistic model checking in PRISM and discrete-event simulation in SimPy with formal development in Event-B. Such an integration allows us to assess how changes and di erent recon guration strategies a ect the overall system resilience. The approach proposed in this thesis is validated by a number of case studies from such areas as robotics, space, healthcare and cloud domain.

Achieving competitive e-commerce in Finnish B2C retail business

E-commerce is one of the most fast growing business areas today and an extremely important channel in retail. In order for companies to succeed in this business environment, it is highly important to understand consumers and how they perceive and select webstores. The objective of the study is to investigate how to achieve competitive e-commerce by investigating consumers and the factors based on which they select a webstore. In addition, the study also seeks to explore whether sex or consumers’ buying experience have an effect on consumer’s webstore selection. Managerial implications are viewed from case company’s perspective. In order to answer the research questions a quantitative marketing survey was conducted. The data was collected by online questionnaire using the case company’s customers as respondents. A total of 1613 responses were obtained from Finnish consumers. Responses were analyzed using ANOVA, factor analysis and t-test. The results show that the most important factors in consumer’s webstore selection are usability, reliability and vendor related information. The biggest difference between heavy and light shoppers is trust formation. Light shoppers value physical stores and familiar vendors, whereas heavy shoppers judge vendor based on the information and usability. Women perceive higher risk than men. The winning strategy requires a hybrid of cost leadership and differentiation.

Quality of outsourced IT services in different degrees of offshoring

The Finnish IT service market can be described to be at a turning point. The clients are ever more interested on services delivered from offshore but certain issues keep them cautious. There is a lack of knowledge on what implications different degrees of offshoring have on service quality. Although there has been significant amount of research related to both service quality and offshoring, several questions are unanswered, terminology remains ambivalent and research findings are inconsistent. The study focuses on the interception of these two fields. The purpose of the study is to learn more about service quality in different degrees of offshoring. At the same time it aims to contribute in narrowing the research gaps. The degree of offshoring can be divided to three delivery modes: onshore, collaboration and offshore. The study takes a mixed method approach where the quantitative and qualitative phases are executed sequentially. First data was gathered from incident management system. Resolution time in different degrees of offshoring was analyzed with Kruskal-Wallis and Jonckheere-Terpstra tests. In addition, the compliance to Service Level Agreement (SLA) in different degrees of offshoring was examined with cross tabulation. The findings from the quantitative analysis suggested that the services with offshore delivery mode perform the best in terms of promptness and SLA compliance. However, several issues were found related to the data and for that reason, the findings should be considered with prudence. After the quantitative analysis, the study moved on to qualitative data collection and analysis. Four semi-structured interviews were held. The interviewees represented different organizational roles and had experiences from different delivery modes. Several themes were covered in the interviews, including: the concept of quality, the subjectivity or objectivity of service quality, expectations and prejudices towards offshore deliveries, quality produced in India, proactiveness of offshore resources, quality indicators and the scarcity of collaborative deliveries. Several conclusions can be made from the empirical research. Firstly, the quality in different delivery modes was found to be controversial topic. Secondly, in the collaborative delivery covered in the study, the way tasks and resources are allocated seem to cause issues. On the other hand inexperienced offshore resources are assigned to the delivery and on the other hand only routine tasks are assigned to the resources. This creates a self-enforcing loop that results in low motivation, low ownership and high employee turnover in offshore. Nevertheless, this issue is not characteristic only to collaborative deliveries but rather allocation of tasks and resources. Moreover, prejudices were identified to affect the perceived service quality in non-predictable way. The research also demonstrated that there is a need in focal company for further data gathering and analysis.

Suorituskyvyn johtaminen metalliteollisuuden yrityksessä

Tutkimuksen tavoitteena on selvittää, mitkä tekijät ovat tärkeimpiä yrityksen suorituskyvyn johtamisessa metalliteollisuusyrityksessä. Tavoitteena on myös löytää tekijät, joilla henkilökunta saadaan motivoitua ja sitoutettua yrityksen toimintaan. Lisäksi tavoitteena on saada selvitettyä kohdeyrityksen suorituskyvyn johtamisen nykytila. Tutkimus on empiirinen tutkimus, jossa käytetään kvantitatiivista eli määrällistä analyysia. Tutkimuksen teoreettisessa osuudessa tarkastellaan tutkimuksen aihetta perehtymällä aikaisempiin tutkimuksiin ja kirjallisuuteen. Kohdeyrityksen nykytilan kartoituksessa käytettiin valmista SUMO-kartoitusta, joka mittaa työmotivaation ja toiminnan tehostumisen taustalla vaikuttavia tekijöitä. Suorituskyvyn menestyksellinen johtaminen metalliteollisuusyrityksessä vaatii toimivaa suorituskyvyn mittaamisjärjestelmää, jota analysoimalla pystytään tekemään päätöksiä tulevaisuuden toimenpiteistä. Suorituskyvyn mittaaminen pitäisi lisäksi kytkeä palkitsemiseen. Työntekijöiden työmotivaatioon ja sitoutumiseen voidaan vaikuttaa monella tapaa. Työmotivaatioon ja sitoutumiseen vaikuttavat työntekijöiden vaikutus- ja koulutusmahdollisuudet sekä palkitseminen, viestintä ja tavoitteet. Näiden tekijöiden luomisessa johtaminen on avainasemassa.

The impact of companies’ demergers to the stock prices: a Finnish perspective

Tässä kauppatieteiden kandidaatintyössä tutkittiin millaisia vaikutuksia julkisesti noteerattujen yhtiöiden osakekurssissa tapahtuu, kun jo valmiiksi Helsingin pörssissä listattu yritys jakautuu kahdeksi uudeksi pörssiyritykseksi. Molempien yrityksien osakkeita voi tämän jakautumisen jälkeen vapaasti ostaa tai myydä. Aikaisempi tutkimus on pääsääntöisesti keskittynyt Yhdysvaltojen markkinoille ja näiden tutkimusten tuloksien perusteella on monessa tapauksessa havautta, että on mahdollista saavuttaa ylinormaaleja tuottoja, kun pörssiyritys jakautuu kahdeksi uudeksi pörssiyritykseksi. Tässä analyysissä jakautumiset ajallisesti tapahtuivat vuosien 1994 ja 2013 välisenä aikana Suomessa ja näitä jakautumia oli yhteensä 16 kappaletta. Tutkimuksessa on hyödynnetty tilastollisten menetelmien analyysiä sekä CAP-mallia, jotta voitaisiin löytää vastauksia seuraaviin kysymyksiin: Vaikuttaako pörssiyrityksen jakautuminen kahdeksi pörssiyritykseksi alkuperäisen yhtiön ja uuden yhtiön osakekursseihin? Onko vaikutus positiivinen, negatiivinen vai onko jakautumisella mitään havaittavaa vaikutusta? Tämän tutkimuksen tulokset antavat uutta tietoa tutkijoille, analyytikoille, opettajille, opiskelijoille, yrityksille ja yritysten johdolle sekä erityisesti sijoittajille. Tulosten mukaan on nähtävissä monia vaikutuksia osakekursseissa, kun pörssiyritys jakautuu. Vaikutus näyttää kuitenkin olevan jossain määrin yritys-riippuvainen. Kun sijoitetaan oikeaan aikaan, on monia jakautuvia yrityksiä, jotka antavat hyvän tuoton keskimäärin, mutta kuten tavallista ja tyypillistä osakemarkkinoille, on myös jakautuvia yhtiöitä, jotka antavat negatiivisia tuottoja tai tuotot ovat nollassa

Jätteiden kemiallisten ominaisuuksien spektrometriset online-mittausmenetelmät

Tässä diplomityössä käsiteltiin spektrometrisia online-mittausmenetelmiä jätteiden kemiallisten ja fysikaalisten ominaisuuksien määrittämiseksi. Tavoitteena oli selvittää, mitä ominaisuuksia menetelmillä voidaan mitata ja kuinka luotettavia tuloksia mittauksilla saadaan. Diplomityössä suoritettiin kirjallisuuskatsaus, jossa käsiteltiin kolmen spektrometrisen menetelmän soveltuvuutta reaaliaikaisiin jätemittauksiin. Työn empiirisessä osassa FPXRFanalysaattorilla mitattiin neljän eri jätenäytteen alkuainepitoisuuksia. Mittauksen tarkoituksena oli selvittää, mitä alkuaineita menetelmällä voidaan mitata. FPXRF-analysaattorilla saatuja tuloksia verrattiin ICP-MS-menetelmällä saatuihin tuloksiin regressioanalyysin avulla. Työssä todettiin, että FPXRF-analysaattori sopii parhaiten kaliumin, kalsiumin, ja raudan pitoisuuksien määrittämiseen. Lisäksi lyijyn, sinkin, kromin, kloorin, kuparin, kadmiumin, arseenin, fosforin, molybdeenin ja vanadiinin määrittäminen on mahdollista, mutta tarkan pitoisuuden saamiseksi laboratoriomenetelmien käyttö voi olla tarpeen. Tutkituista jätenäytteistä menetelmä soveltui parhaiten tuhkalle ja kompostille niiden fyysisten ominaisuuksien, kuten homogeenisuuden ja kosteuspitoisuuden takia. Biojätteelle menetelmä soveltui huonosti. FPXRF-analysaattorin luotettavuuteen vaikuttaa näytteen kosteuspitoisuus, homogeenisuus, partikkelikoko, mittaustapa ja laitteen kalibrointi. Työssä tarkastelluilla menetelmillä ei voida tällä hetkellä täysin korvata laboratorioanalyyseja. FPXRF-analysaattoria voidaan kuitenkin käyttää kvalitatiiviseen tai semikvantitatiiviseen haitta-aineiden analysointiin, millä voidaan vähentää kalliiden laboratorioanalyysien tarvetta.

Viability of part cargoes in tramp shipping company’s routing and scheduling decisions

Operational excellence of individual tramp shipping companies is important in today’s market, where competition is intense, freight revenues are modest and capital costs high due to global financial crisis, and tighter regulatory framework is generating additional costs and challenges to the industry. This thesis concentrates on tramp shipping, where a tramp operator in a form of an individual case company, specialized in short-sea shipping activities in the Baltic Sea region, is searching ways to map their current fleet operations and better understand potential ways to improve the overall routing and scheduling decisions. The research problem is related to tramp fleet planning where several cargoes are carried on board at the same time, which are here systematically referred to as part cargoes. The purpose is to determine the pivotal dimensions and characteristics of these part cargo operations in tramp shipping, and offer both the individual case company and wider research community better understanding of potential risks and benefits related to utilization of part cargo operations. A mixed method research approach is utilized in this research, as the objectives are related to complex, real-life business practices in the field of supply chain management and more specifically, maritime logistics. A quantitative analysis of different voyage scenarios is executed, including alternative voyage legs with varying cost structure and customer involvement. An on-line-based questionnaire designed and prepared by case company’s decision group again provides desired data of predominant attitudes and views of most important industrial customers regarding the part cargo-related operations and potential future utilization of this business model. The results gained from these quantitative methods are complied with qualitative data collection tools, along with suitable secondary data sources. Based on results and logical analysis of different data sources, a framework for characterizing the different aspects of part cargo operations is developed, utilizing both existing research and empirical investigation of the phenomenon. As conclusions, part cargoes have the ability to be part of viable fleet operations, and even increase flexibility among the fleet to a certain extent. Naturally, several hinderers for this development is recognized as well, such as potential issues with information gathering and sharing, inefficient port activities, and increased transit times.