Browsing by Department "Tietotekniikan laitos"
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Item3D-tulostuksen työkaluketjun analysointi kotikäytön näkökulmasta(2015-04-19) Hirvola, Ossi; Nurminen, Jukka; Tietotekniikan laitos; Perustieteiden korkeakoulu; Rousu, Juho Item5G innovaatiot teollisuuden digitalisaation kiihdyttämiseksi - Datavetoiset käyttötapaukset(Aalto University, 2023) Collin, Jari; Pellikka, Jarkko; Penttinen, Jyrki TJ; Öfversten, Janne; Koivula, Ella; Laiho, Perttu; Lahti, Roope; Rajani, Jagdeesh; Laars, Maarten van der; Tietotekniikan laitos; Department of Computer Science; Perustieteiden korkeakoulu; School of ScienceThe digitalisation of products and services is shaping competition and existing industry boundaries. Today, traditional physical product-based business models are challenged by data-driven digital ecosystems that enable new ways to increase end-customer value. Modern digital platforms and the utilisation of real-time data enable significant value added – as numerous IoT (Internet of Things) applications for consumers have already demonstrated. In the corporate market, the lack of common business rules for sharing data between companies has hampered similar developments in Industrial IoT applications, even though the business opportunities of data-driven digital services are obvious. 5G mobile technology enables an open and reliable platform for industrial ecosystems to collaborate securely globally. The research deals with the ongoing industrial transformation and data-driven digital services that can be accelerated with the help of 5G technology. The purpose of the study is to identify and describe industrial 5G use cases to promote customer value, productivity, and sustainability in a selected industrial ecosystem. The research problem is how 5G can be utilised in the digital transformation of industry. Five different sectors are included in the study: mining, forestry, construction/elevator, telecommunications and oil refining, each of which has a pioneering case company. The research perspective is an industrial company seeking new business opportunities with the help of industrial 5G. Sharing lessons learned and best practices across industries is an essential part of research. The study represents the so-called. Multiple case study, which aims to create new theory from modern use cases and observations. The research results in a new understanding of how industrial 5G can be utilised in the digital transformation of industry, what are the biggest obstacles and prerequisites for successful deployment. The result will also identify new opportunities and areas where new 5G mobile technology opens up opportunities to create operational innovations and new digital services. The case studies also identified and described areas common to the industry sectors and areas that are very sector-specific. Based on the experience gained, three alternative approaches to implementing an industrial 5G network solution will be presented. Applications related to different use cases can also be implemented in several different ways, based on the purpose and environment of the applications. Item5G-verkkoteknologian kehitys ja vaikutus esineiden internetiin(2018-04-25) Helkavaara, Ilkka; Ylä-Jääski, Antti; Tietotekniikan laitos; Perustieteiden korkeakoulu; Kannala, Juho ItemA/B testing and usability assessment methods in small companies(2014) Luzik, Maksim; Turku, Charlotta; Tietotekniikan laitos; Perustieteiden korkeakoulu; Kauppinen, MarjoUsability assessment methods have been considered for long as useful tools to improve usability of the product or service. Many small companies are still reluctant to practice usability assessment methods due to many reasons including limited resources and management bias. A/B testing is a new movement in a corporate world. Multiple companies are considering to begin practicing the method or are practicing it already. Moreover, some people assume that A/B testing can actually cover all the usability assessment methods. This work provides answers to what A/B testing and usability assessment methods are and how they can be practiced in a small company (10-100 employees). Additionally the strengths and weaknesses of both methods are presented and compared. Finally suitability of the methods will be discussed. The target of optimization in this paper is an application of A/B test into a complex enterprise system. Only common usability assessment methods will be evaluated that are used today. These include standard usability testing, heuristic evaluation and cognitive walkthrough. No other usability assessment methods are included in tnis paper. Both practices: usability assessment methods and A/B testing have a place in a project. Despite their different approach they often complement each other and give answers to different questions. Usability assessment methods tend to answer to question why while A/B test usually answers to question which or how many. Usability assessment methods work well as an initial evaluation while A/B test can be used as a follow up method to fine-tune product or service even further. ItemAccess control and group management in a mobile peer-to-peer system(2009) Soinio, Tuomo Juhani; Beijar, Nicklas; Tietotekniikan laitos; Teknillinen korkeakoulu; Helsinki University of Technology; Kantola, Raimo ItemAccess Control and Machine Learning: Evasion and Defenses(Aalto University, 2019) Juuti, Mika; Tietotekniikan laitos; Department of Computer Science; Secure Systems Group; Perustieteiden korkeakoulu; School of Science; Asokan, N., Prof., Aalto University, Department of Computer Science, FinlandMachine learning (ML) and artificial intelligence (AI) systems have experienced significant proliferation during the recent years, for example in the new market of "machine learning as a service". ML is also increasingly being deployed in security-critical applications, such as access control systems. ML can be used to make security systems easier to use, or to defend against specific attacks, such as the "relay attack". Such ML applications are particularly sensitive to the recent development of "adversarial machine learning", where weaknesses in machine learning systems are exploited to undermine some security-critical property. For example, "evasion attacks" undermine a ML system's prediction integrity, while "model extraction attacks" undermine the system's confidentiality. It has become increasingly important to evaluate ML applications against such undesired behavior. The work described in this dissertation is divided into three parts. In the first part, I evaluate how security properties in so-called transparent authentication systems can be improved using machine learning, and describe how to evaluate security against strong adversaries. In the second part, I present state-of-the-art evasion and model extraction attacks against image classification systems. In the third part, I evaluate state-of-the-art hate speech classifiers against evasion attacks, and present a method of artificially creating credible fake restaurant reviews. Finally, I present general observations and conclusions about both transparent authentication, and the feasibility of using ML for purposes such as moderation. ItemAccess control in a web-based business management application(2008) Mattila, Tommy; Kohonen, Oskar; Tietotekniikan laitos; Teknillinen korkeakoulu; Helsinki University of Technology; Sulonen, ReijoThe amount of Web applications used to replace existing traditional business applications has recently increased significantly. This makes it important to have proper security mechanisms for the web applications. Access control is the management of access to information and resources. Role-based access control (RBAC) is a policy neutral and very flexible access control system. In RBAC permissions are assigned to roles instead of directly to users. The thesis concentrates on the access control part of a web application. The thesis builds the foundation for implementing an access control system for a web-based business management application. The thesis presents different types of access control models and establishes which are the most suitable for the given application. After establishing RBAC as the most suitable model, it is implemented in the business management application. ItemAccess control in building automation and control systems(2012) Soni, Amit; Kumar, Sandeep; Morchon Garcia, Oscar; Keoh, Sye Loong; Tietotekniikan laitos; Perustieteiden korkeakoulu; School of Science; Aura, TuomasBuilding Automation and Control Systems (BACS) are being deployed in commercial buildings to enable monitoring and control of the various intelligent systems like HVAC, safety, access and lighting systems. Lighting is an integral part of BACS, allowing for optimized lighting operation where Lighting devices interact with each other, with users, and with other third party systems such as energy management. A key need when interacting is the controlled and trustworthy access to services so that only authenticated and authorized entities can have access and control to the services provided by a device. However, secure authentication and authorization is not easy due to the large-scale nature of future BACS comprising many resource-constrained sensors and actuators distributed in the building. The thesis presents centralized and distributed access control architecture designs for BACS based on their requirements and constraints. We further present a hybrid version of an access control architecture which improves existing centralized or distributed access control methods. The hybrid version allows for the deployment of re-encoded access control policies to the accessed devices under request. Re-encoding serves the purpose of efficient storage and evaluation of the policies in the resource constrained devices. The proposed access control systems can be applied to generic BACS and run on top of communication protocols such as ZigBee or 6LoWPAN/CoAP. We have further implemented a prototype to prove the concept on actual field devices used by Philips Lighting. The operating system used by devices is Contiki-OS. The final system requires 10KBs of FLASH and allows caching of access control policies in the device. The access control system can be used in applications scenarios related to the Internet of Things. ItemAccessing multiversion data in database transactions(Aalto-yliopiston teknillinen korkeakoulu, 2010) Haapasalo, Tuukka; Sippu, Seppo, Prof.; Tietotekniikan laitos; Department of Computer Science and Engineering; Aalto-yliopiston teknillinen korkeakoulu; Soisalon-Soininen, Eljas, Prof.Many important database applications need to access previous versions of the data set, thus requiring that the data are stored in a multiversion database and indexed with a multiversion index, such as the multiversion B+-tree (MVBT) of Becker et al. The MVBT is optimal, so that any version of the database can be accessed as efficiently as with a single-version B+-tree that is used to index only the data items of that version, but it cannot be used in a full-fledged database system because it follows a single-update model, and the update cannot be rolled back. We have redesigned the MVBT index so that a single multi-action updating transaction can operate on the index structure concurrently with multiple concurrent read-only transactions. Data items created by the transaction become part of the same version, and the transaction can roll back. We call this structure the transactional MVBT (TMVBT). The TMVBT index remains optimal even in the presence of logical key deletions. Even though deletions in a multiversion index must not physically delete the history of the data items, queries and range scans can become more efficient, if the leaf pages of the index structure are merged to retain optimality. For the general transactional setting with multiple updating transactions, we propose a multiversion database structure called the concurrent MVBT (CMVBT), which stores the updates of active transactions in a separate main-memory-resident versioned B+-tree index. A system maintenance transaction is periodically run to apply the updates of committed transactions into the TMVBT index. We show how multiple updating transactions can operate on the CMVBT index concurrently, and our recovery algorithm is based on the standard ARIES recovery algorithm. We prove that the TMVBT index is asymptotically optimal, and show that the performance of the CMVBT index in general transaction processing is on par with the performance of the time-split B+-tree (TSB-tree) of Lomet and Salzberg. The TSB-tree does not merge leaf pages and is therefore not optimal if logical data-item deletions are allowed. Our experiments show that the CMVBT outperforms the TSB-tree with range queries in the presence of deletions. ItemAchievement goal orientation profiles and mobile learning - Studies on motivation and mobile learning in the Degree Programmes on Information Technology and Media Technology at Lahti University of Applied Sciences in 2011 - 2012(2014) Asplund, Minna; Tuominen-Soini, Heta; Tietotekniikan laitos; Perustieteiden korkeakoulu; Malmi, LauriThis thesis analyses achievement goal orientation profiles and mobile learning at Lahti University of Applied Sciences in 2011 - 2012. The research questions are handled from the viewpoint of stu-dents in the Information Technology and Media Technology Degree Programmes, and from the viewpoint of the software engineering lecturers. The purpose of this thesis was to investigate what kinds of achievement goal orientation profiles can be identified among students. Another aim was to find out the factors that influence on students' studying motivation according to their own opinion. One research question concerns how the software engineering students' motivational profiles differ from the view lecturers have on their profiles. These three research questions deal with motivation. Additionally, the purpose was to examine how mobile assignments correlate with course grades. The next research question was how students in different goal orientation profiles manage with mobile assignments. Finally, it was also examined how students experience these mobile assignments. The last three research questions deal with mobile learning. The research was carried out by applying statistical methods, qualitative interviews and the applied Delphi -method. A questionnaire instrument was used to find out the students' achievement goal orientation profiles. The main results were as follows: students were classified into mastery-oriented, success-oriented, indifferent and avoidance-oriented profiles. The software engineering lecturers seemed not to agree with the profiles that software engineering students had. The students themselves felt that projects done for real customers motivated them the most and that the lecturer's preparations, attitude and commitment to the course played a significant role. The results from the mobile assignments suggest that they were beneficial to all students regardless from the orientation profile. Because indifferent and avoidance-oriented students seemed to get better course results when using different learning spaces they should be taken into use. Students experienced mobile assignments mainly positively, and thought that mobile learning will be part of normal studying in the next five years ItemAcoustic Scattering for Spatial Audio Applications(Aalto University, 2022) Gonzalez, Raimundo; Politis, Archontis, Dr., Tampere University of Technology, Finland; Tietotekniikan laitos; Department of Computer Science; Perustieteiden korkeakoulu; School of Science; Lokki, Tapio, Prof., Aalto University, Department of Signal Processing and Acoustics, FinlandModeling of sound propagation on the context of acoustic design and interactive applications have mainly focused on room acoustics as well as source and receiver modeling. In order to enrich the description and perceptual immersion of virtual sound-fields, modeling frameworks can also include the effects of scattering of bodies within the physical space. One of the main challenges in modeling the effects of scattering, is that its behaviour not only depends on the geometry of the scatterer but also the direction of arrival of the incident field. This thesis is a collection of five publications, the first two studies focus on the effects of near-field sources, and the last three studies involve the effects of scattering within spatial audio applications. The first publication explores the effects of near-field sources on High-order Ambisonics recording, processing and binaural reproduction. Results indicate that while near-field sources introduce low-frequency proximity gains in high-order microphones arrays, the regularization stages in Ambisonics recording prevents excessive gains. The second publication explores the directivity of near-field speech of 24 subjects and evaluates various repeatable speech reproduction alternatives. The third publication presents a scheme for encoding the acoustic scattering of arbitrary geometries into the spherical harmonic domain. After encoding, the scattering is represented as a multiple-input multiple-output matrix which describes the relation between the incoming and outgoing scattering modes of a geometry. This method allows for the standard transformations in the spherical harmonic domain (rotation, translation, scaling) and it is compatible with existing spatial audio frameworks such as Ambisonics and image-source methods. This method is validated using boundary element method simulations and indicates minimal synthesis error. The fourth publication presents a method to encode the space domain signals from a microphone array with arbitrary geometry and irregularly distributed sensors into Ambisonics. The algorithm relies on the array response and its enclosure's scattering properties to solve the direction of various active sources as well as the diffuse properties of the sound-field. Objective and subjective evaluations indicate that the proposed method outperforms traditional linear encoding. The fifth publication extends the method presented in the third publication by allowing sector-based encoding of acoustic scattering, optimal for geometries and surfaces which do not require entire spherical radiation. This last publication also presents a method to compress the data of the scattering matrix, allowing for more efficient memory storage. Methods proposed in the third and fifth publications can be used to introduce scattering geometries into interactive sound environments to produce more descriptive sound-fields while the fourth publication can be used to develop Ambisonic recording arrays on practical devices such as wearables and head-mounted displays. ItemActively secure two-party computation: Efficient Beaver triple generation(2013) Pullonen, Pille; Bogdanov, Dan; Tietotekniikan laitos; Perustieteiden korkeakoulu; School of Science; Aura, Tuomas|Laur, Sven