Analyysityökalun kehittäminen C#-kielisten lähdekoodien tarkastamiseen

Katselmoinnit ja tarkastusmenettelyt ovat osa ohjelmistotuotantoprosessin laadunvarmistusta. Staattisella tarkastamisella tarkoitetaan ohjelmistotuotteen visuaalista tarkastamista ohjelmistovirheiden havaitsemiseksi ja korjaamiseksi. Ohjelmiston lähdekoodin tarkastaminen voidaan suorittaa automaattisesti tarkoitukseen sopivalla ohjelmistolla l. analyysityökalulla. Tässä työssä toteutettiin analyysityökalu C#-kielisten lähdekoodien tarkastamiseen. Työkalulla suoritetussa kenttätestauksessa havaittiin tarkastettavissa ohjelmistoissa ohjelmiston ylläpitoon vaikuttavia puutteita. Lisäksi työssä tarkasteltiin katselmointeja osana ohjelmistotuotantoprosessin laadunvarmistusta sekä erilaisia ohjelmistovirheitä ja niiden lähteitä.

Novel Methods for Error Modeling and Parameter Identification of a Redundant Serial-Parallel Hybrid Robot

To obtain the desirable accuracy of a robot, there are two techniques available. The first option would be to make the robot match the nominal mathematic model. In other words, the manufacturing and assembling tolerances of every part would be extremely tight so that all of the various parameters would match the “design” or “nominal” values as closely as possible. This method can satisfy most of the accuracy requirements， but the cost would increase dramatically as the accuracy requirement increases. Alternatively, a more cost-effective solution is to build a manipulator with relaxed manufacturing and assembling tolerances. By modifying the mathematical model in the controller, the actual errors of the robot can be compensated. This is the essence of robot calibration. Simply put, robot calibration is the process of defining an appropriate error model and then identifying the various parameter errors that make the error model match the robot as closely as possible. This work focuses on kinematic calibration of a 10 degree-of-freedom (DOF) redundant serial-parallel hybrid robot. The robot consists of a 4-DOF serial mechanism and a 6-DOF hexapod parallel manipulator. The redundant 4-DOF serial structure is used to enlarge workspace and the 6-DOF hexapod manipulator is used to provide high load capabilities and stiffness for the whole structure. The main objective of the study is to develop a suitable calibration method to improve the accuracy of the redundant serial-parallel hybrid robot. To this end, a Denavit–Hartenberg (DH) hybrid error model and a Product-of-Exponential (POE) error model are developed for error modeling of the proposed robot. Furthermore, two kinds of global optimization methods, i.e. the differential-evolution (DE) algorithm and the Markov Chain Monte Carlo (MCMC) algorithm, are employed to identify the parameter errors of the derived error model. A measurement method based on a 3-2-1 wire-based pose estimation system is proposed and implemented in a Solidworks environment to simulate the real experimental validations. Numerical simulations and Solidworks prototype-model validations are carried out on the hybrid robot to verify the effectiveness, accuracy and robustness of the calibration algorithms.

Supplier codes of conduct: Acting responsibly in global supply chains

Nowadays the Western companies are considered responsible for the social and environmental issues in their whole supply chains. To influence the practices of their suppliers the Western companies have created suppliers codes of conduct (SCCs) which express their requirements. Suppliers’ compliance with the SCCs is checked through audits. The purpose of this thesis is to analyze SCCs as a means for Western companies to ensure socially and environmentally responsible actions in their global supply chains, and the sub-objectives are to find out 1) how well do the SCCs and their auditing work at suppliers’ production sites and 2) how can possible problems related to SCCs and their auditing be solved. This is a qualitative research carried out in the form of a case study with two case companies. In this study both primary and secondary data is used. The primary data is collected in the form of interviews of the case company representatives and three external experts. Based on a theoretical framework of previous research in the fields of corporate social responsibility and supply chain management, a model with eleven factors, which influence the success of SCC implementation and the auditing of SCC –implementation, is drafted. Also several different best-practices to help to solve and avoid possible problems related to SCC -implementation and auditing have been identified from previous research. Based on the findings of this study the theoretical model has been updated adding two new influential factors. It seems that how well the SCC and its auditing work at suppliers’ production sites depends on the joint effect of thirteen influential factors: buyer’s purchasing policy, supplier’s motivation, buyer’s commitment, the solving of agency problems, the contents of the SCC, supplier’s role and the buyer-supplier –relationship, complexity of supply chain, the limitations of the smaller buyers, cooperation through a business association or multi-stakeholder system, the role of supplier’s employees, SCC –related communication and supplier’s understanding, cheating in audits and the auditors. The possible problems related to SCCs and their auditing can be solved by adopting best-practices. Nine of the theoretical best-practices stand out from the findings of this study: 1) two-way communication and collecting feedback from suppliers, 2) the philosophy of continuous improvement, 3) long-term business relationships with the supplier, 4) informing the supplier about the advantages of SCC –compliance, 5) rewarding code-compliant suppliers, 6) building collaborative, good buyer-supplier relationships, 7) supporting and advising the supplier, 8) joining a business association or multi-stakeholder system and 9) interviewing supplier’s employees as a part of the audits.

On Distributed Storage Codes

Distributed storage systems are studied. The interest in such system has become relatively wide due to the increasing amount of information needed to be stored in data centers or different kinds of cloud systems. There are many kinds of solutions for storing the information into distributed devices regarding the needs of the system designer. This thesis studies the questions of designing such storage systems and also fundamental limits of such systems. Namely, the subjects of interest of this thesis include heterogeneous distributed storage systems, distributed storage systems with the exact repair property, and locally repairable codes. For distributed storage systems with either functional or exact repair, capacity results are proved. In the case of locally repairable codes, the minimum distance is studied. Constructions for exact-repairing codes between minimum bandwidth regeneration (MBR) and minimum storage regeneration (MSR) points are given. These codes exceed the time-sharing line of the extremal points in many cases. Other properties of exact-regenerating codes are also studied. For the heterogeneous setup, the main result is that the capacity of such systems is always smaller than or equal to the capacity of a homogeneous system with symmetric repair with average node size and average repair bandwidth. A randomized construction for a locally repairable code with good minimum distance is given. It is shown that a random linear code of certain natural type has a good minimum distance with high probability. Other properties of locally repairable codes are also studied.