Browsing by Author "Nurminen, Jukka K."

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Analysis of Potential Shift to Low-Carbon Urban Travel Modes: A Computational Framework Based on High-Resolution Smartphone Data
(2020-08) Bagheri Majdabadi, Mehrdad; Mladenovic, Milos; Kosonen, Iisakki; Nurminen, Jukka K.
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
Given the necessity to understand the modal shift potentials at the level of individual travel times, emissions, and physically active travel distances, there is a need for accurately computing such potentials from disaggregated data collection. Despite significant development in data collection technology, especially by utilizing smartphones, there are limited efforts in developing useful computational frameworks for this purpose. First, development of a computational framework requires longitudinal data collection of revealed travel behavior of individuals. Second, such a computational framework should enable scalable analysis of time-relevant low-carbon travel alternatives in the target region. To this end, this research presents an open-source computational framework, developed to explore the potential for shifting from private car to lower-carbon travel alternatives. In comparison to previous development, our computational framework estimates and illustrates the changes in travel time in relation to the potential reductions in emission and increases in physically active travel, as well as daily weather conditions. The potential usefulness of the framework was evaluated using long-term travel data of around a hundred travelers within the Helsinki Metropolitan Region, Finland. The case study outcomes also suggest that in several cases traveling by public transport or bike would not increase travel time compared to the observed car travel. Based on the case study results, we discuss potentially acceptable travel times for mode shift, and usefulness of the computational framework for decisions regarding transition to sustainable urban mobility systems. Finally, we discuss limitations and lessons learned for data collection and further development of similar computational frameworks.
Browser to browser media streaming with HTML5
(2012) Meyn, Antony J. R.
Perustieteiden korkeakoulu | Master's thesis
Video on demand services generate one of the largest portions of Internet traffic every day and their use is constantly increasing. Scaling up the infrastructure to meet this demand with the current model of Internet video delivery over HTTP, is proving to be very costly for service providers. An alternative model for video content delivery is the need of the hour to meet this challenge. Peer-to-peer streaming is a viable alternative model that is highly scalable and can meet this increasing demand. The emerging HTML5 standard introduces APIs that give Web browsers the ability to communicate directly with each other in real-time. This also allows web browsers to behave as Peer-to-peer nodes. In this thesis, we utilize these new APIs to develop a Video on demand service within the Web browser. The goal of this being to determine the feasibility of such a solution and evaluate the usage of these APIs. We hope to aid the HTML standardization process with our findings.
Cellular-based vehicle to pedestrian (V2P) adaptive communication for collision avoidance
(2015-10-12) Bagheri Majdabadi, Mehrdad; Siekkinen, Matti; Nurminen, Jukka K.
A4 Artikkeli konferenssijulkaisussa
Road safety is one of the most important applications of vehicular networks. However, improving pedestrian safety via vehicle-to-pedestrian (V2P) wireless communication has not been extensively addressed. In this paper, our vision is to propose a method which enables development of V2P road safety applications via wireless communication and only utilizing the existing infrastructure and devices. As pedestrians' smartphones do not support the IEEE 802.11p amendment which is customized for vehicular networking, we have initiated an approach that utilizes cellular technologies. Study shows potential of utilizing 3G and LTE for highly mobile entities of vehicular network applications. In addition, some vehicles are already equipped with cellular connectivity but otherwise the driver's smartphone is used as an alternative. However, smartphone limited battery life is a bottleneck in realization of such pedestrian safety system. To tackle the energy limitation in smartphones, we employ an adaptive multi-level approach which operates in an energy-saving mode in risk-free situations but switches to normal mode as it detects a risky situation. Based on our evaluation and analysis, this adaptive approach considerably saves electrical energy and thus makes the cellular-based road-safety system practical.
Cloud-Based Pedestrian Road-Safety with Situation-Adaptive Energy-Efficient Communication
(2016-07-21) Bagheri Majdabadi, Mehrdad; Siekkinen, Matti; Nurminen, Jukka K.
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
Pedestrian detection using wireless communication complements sensor-based pedestrian detection in driverless and conventional cars. This fusion improves road-safety particularly in obstructed visibility and bad weather conditions. This paper seeks developing such wireless-based vehicle-to-pedestrian (V2P) collision avoidance using energy-efficient methods and non-dedicated existing technologies namely smartphones (widespread among pedestrians and drivers), cellular network and cloud. Our road-safety mobile app can be set to driver mode or pedestrian mode. This app frequently sends vehicle and pedestrian geolocation data (beacons) to cloud servers. Cloud performs threat analysis and sends alerts to road users who are in risky situation. However, constant pedestrian-to-cloud (P2C) beaconing can quickly drain smartphone battery and make the system impractical. We employ adaptive multi-mode (AMM) approach built on situation-adaptive beaconing. AMM reduces power consumption using beacon rate control while it keeps the data freshness required for timely vehicle-to-pedestrian collision prediction. AMM runs on cloud servers and commands the mobile apps to change P2C beaconing frequency according to collision risk level from the surrounding vehicular traffic. City-scale mobility simulation demonstrates energy efficiency of our approach. We evaluate battery lifetime according to geolocational variations over the city map. Results show that road-safety system imposes a small mean overhead on smartphone battery's state-of-charge. Furthermore, our evaluation of computation and network load shows feasibility of running such road-safety systems on conventional cellular networks and cloud providers. We use server-side prototype experiment to estimate minimum cloud resources and cloud service costs needed to handle computation of city-scale geolocation data.
A computational framework for revealing competitive travel times with low carbon modes based on smartphone data collection
(2020) Bagheri Majdabadi, Mehrdad; Mladenovic, Milos; Kosonen, Iisakki; Nurminen, Jukka K.; Roncoli, Claudio; Ylä-Jääski, Antti
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
Evaluating potential of shifting to low-carbon transport modes requires considering limited travel-time budget of travelers. Despite previous studies focusing on time-relevant modal shift, there is a lack of integrated and transferable computational frameworks, which would use emerging smartphone-based high-resolution longitudinal travel datasets. This research explains and illustrates a computational framework for this purpose. The proposed framework compares observed trips with computed alternative trips and estimates the extent to which alternatives could reduce carbon emission without a significant increase in travel time. The framework estimates potential of substituting observed car and public-transport trips with lower-carbon modes, evaluating parameters per individual traveler as well as for the whole city, from a set of temporal and spatial viewpoints. The illustrated parameters include the size and distribution of modal shifts, emission savings, and increased active-travel growth, as clustered by target mode, departure time, trip distance, and spatial coverage throughout the city. Parameters are also evaluated based on the frequently repeated trips. We evaluate usefulness of the method by analyzing door-to-door trips of a few hundred travelers, collected from smartphone traces in the Helsinki metropolitan area, Finland, during several months. The experiment's preliminary results show that, for instance, on average, 20% of frequent car trips of each traveler have a low-carbon alternative, and if the preferred alternatives are chosen, about 8% of the carbon emissions could be saved. In addition, it is seen that the spatial potential of bike as an alternative is much more sporadic throughout the city compared to that of bus, which has relatively more trips from/to city center. With few changes, the method would be applicable to other cities, bringing possibly different quantitative results. In particular, having more thorough data from large number of participants could provide implications for transportation researchers and planners to identify groups or areas for promoting mode shift. Finally, we discuss the limitations and lessons learned, highlighting future research directions.
Connecting IoT Sensors to Knowledge-Based Systems by Transforming SenML to RDF
(2014) Su, Xiang; Zhang, Hao; Riekki, Jukka; Keränen, Ari; Nurminen, Jukka K.; Du, Libin
A4 Artikkeli konferenssijulkaisussa
Applying Semantic Web technologies to Internet of Things (IoT) enables smart applications and services in a variety of domains. However, the gap between semantic representations and data formats used in IoT devices introduces a challenge for utilizing semantics in IoT. Sensor Markup Language (SenML) is an emerging solution for representing device parameters and measurements. SenML is replacing proprietary data formats and is being accepted by more and more vendors. In this paper, we suggest a solution to transform SenML data into a standardized semantic model, Resource Description Framework (RDF). Such a transformation facilitates intelligent functions in IoT, including reasoning over sensor data and semantic interoperability among devices. We present a fishery IoT system to illustrate the usability of this approach and compare the resource consumptions of SenML against other alternatives.
Consistency-responsiveness Tradeoff Evaluation for Consistency Maintenance in Multiplayer Online Games
(2016-04-04) Toiviainen, Joni
Perustieteiden korkeakoulu | Master's thesis
Multiplayer online gaming has become a massive part of the game industry. Games that use network connections are known to be vulnerable to communication problems like latency, jitter and packet loss. These problems may cause players to suffer from delayed responsiveness or weird game entity behaviors. Games typically fight against network problems by using consistency maintenance methods which need to perform a balancing act between the game's consistency and responsiveness. A huge variety of techniques exists, but there has not been a clear guideline about how a suitable technique should be selected. This Thesis proposes a categorization for the consistency maintenance techniques based on their ability to handle time or data. Categorization is also evaluated with a user study by implementing a single technique from each category and testing them with a simple game. Results from the evaluation are further used to form an analysis for each proposed category. Analysis is used to make small conclusions about the advantages and disadvantages for each category together with a suggestion of how to balance with the consistency-responsiveness ratio to maintain the playability of the game. Pessimistic techniques are considered to provide good consistency in the cost of responsiveness and vice versa for optimistic techniques. PPT is considered as a good solution for a game that does not require real-time simulation, while PDT works well with a game that requires high consistency and may tolerate long response times. OPT is considered as a suitable solution for a game which contains easily predictable shared state entities and ODT is recommended for a game that contains clear decision points.
Coupling Symbolic and Numeric Computing in Knowledge-Based Systems: An Application to Electronics Design
(1989) Nurminen, Jukka K.
Helsinki University of Technology | Licentiate thesis
Design and Implementation of Centralized APIs Platform and Application Portal
(2019-10-21) Päivärinta, Kimi
Perustieteiden korkeakoulu | Master's thesis
Centralized APIs is a solution for KPMG ("Company") to tackle the problem that multiple departments of the Company are developing API logic to public and proprietary databases in parallel. API logic consists of code and logic required to fetch information from an API. The main requirement is that the API logic for each API is developed only once. In addition, Single Sign-On authentication to the Company' systems is needed and API usage must be tracked on a user and a query level. Emphasis must be given to ease of development: development of new API logic to the centralized APIs should be easier than before. This thesis has three goals. First, to design and evaluate the best fitting architecture to fulfil all requirements; second to implement a functioning centralized APIs platform; and third, to implement a real-world example API logic with a new API wrapped around it ("internal API") inside the centralized APIs platform. Internal API will act as a template for future internal API implementations to make the development as easy as possible. Also, a Minimum Viable Product (MVP) level implementation of an application portal (front-end) that utilizes the internal API is implemented. It is also used to evaluate the centralized APIs solution. Internal APIs are implemented as microservices based on Python Flask web back-end framework located in the centralized APIs platform. It includes authentication, documentation, and API gateway services. The application portal is a Single-Page Application (SPA) developed on React front-end framework. Evaluation of the solutions reveals that all requirements are fulfilled for the centralized APIs and all but one is fulfilled for the application portal. Ease of development of internal APIs and Applications is analysed with examples of how they can be implemented. Demand for both solutions exists within the Company.
Designing Web Services for Location-Aware Mobile Devices - Case: Trac Monitoring Service
(2012) Lyytikäinen, Hannu
Master's thesis
Open remote programming interfaces and technologies that enable the development of mashup applications have revolutionized the way the World Wide Web is used. The emergence of smartphones has provided a new platform for which to build applications that people can use regardless of their location. The location-aware features of smartphones have made it possible for the mobile mashup applications to customize the content they provide for users based on their location. In this thesis I study how Web services should be designed and implemented so that they would serve location-aware mobile mashup application in the best possible way. I lay down the requirements that this sort of Web service has and then look into different technological and architectural solutions that are available to create a location-aware mobile-friendly Web service interface. As the practical part of the thesis, I use the knowledge gathered from my theoretical study to implement a new Web service interface for a traffic monitoring system. The new interface is created because the system currently lacks an interface that is mobile-friendly and enables the customization of content based on the location of the user. To prove that the new interface solves the problem at hand, I implement a mobile application that consumes the new Web service interface. The client application is also used to measure sizes of responses returned by the new API, the time used to process them and what kind of effect location-based optimization has on the API. Based on the results of the implementation process and the findings of the testing phase, I propose a set of design guidelines that can be applied when developing a Web service interface for mobile location-aware devices.
Enabling energy-efficient advertising for mobile applications
(2013) Prochkova, Irena
School of Science | Master's thesis
Ethical decision-making in autonomous vehicles
(2017-05-05) Rinne, Juho
Perustieteiden korkeakoulu | Bachelor's thesis
Identity Management in M2M Networks
(2014-08-21) Butkus, Pranas
Perustieteiden korkeakoulu | Master's thesis
Evolving communication technologies stimulate a rapid growth in utilisation of communication-capable devices and therefore amount of transmitted data. This imposes new requirements for automatic device and data management necessary for successful exploitation of new opportunities. Unfortunately, currently developed systems, including Internet of Things and Machine-to-Machine communications, mainly focus on industrial applications that involve fixed users, proprietary environments as well as ad-hoc devices and things, whereas regular users along with possibilities and challenges created by growing sets of personal user equipment remain ignored. This thesis addresses the defined problem by analysing currently developed and utilised communication technologies and identity management systems as well as proposing an advanced identity management system that considers user-related needs and enables user-aware automatic device-to-device communications. Our system is unique compared to other automatic communication systems in that it enables global communication of devices owned or used by different parties and supports dynamic connection and relationship establishment based on data administered in a sophisticated identity management infrastructure. Unlike existing identity management mechanisms, our system extends the notion of an identified and authenticated entity to a combination of both user and device. Furthermore, the system introduces an original Single Device Sign-On feature that simplifies user login procedure when accessing a service with multiple devices. As a consequence, this thesis suggests a new direction for evolution of communication technologies as well as user-targeted Internet-based services and applications.
Improving JavaScript Development Productivity by Providing Runtime Information within the Code Editor
(2015-05-11) Troberg, Alexis
Perustieteiden korkeakoulu | Master's thesis
Softare development is a laborious and expensive activity that highly benefits from productivity improvements. It has been estimated that developers spend 50-80% of their time trying to understand code. Previous studies have shown that developer tools can significantly assist developers in code comprehension and thus improve their productivity. Web applications built with JavaScript have become increasingly popular, but developer tools available for web application development are still immature. This is mainly due to the dynamic nature of JavaScript, which makes it unsuitable for conventional development tools that work by statically analysing source code. This thesis presents previous research on developer productivity and JavaScript developer tools. The most important contribution of this thesis is Tracr, a novel JavaScript development tool that enables live editing of code within a code editor. Live editing has been previously found to be an effective technique for improving code comprehension and developer productivity. Tracr's development workflow and its technical feasibility are evaluated. The results show that the tool improves developer productivity by simplifying the workflow of common development activities. The technical approach is proven to be feasible and can be applied for other programming languages as well. In the future, a user study should be conducted in order to assess the productivity improvement of Tracr.
Improving the efficiency of deploying virtual machines in a cloud environment
(2012) Laurikainen, Risto
Master's thesis
Flexible allocation of resources is one of the main benefits of cloud computing. Virtualization is used to achieve this flexibility: one or more virtual machines run on a single physical machine. These virtual machines can be deployed and destroyed as needed. One obstacle to flexibility in current cloud systems is that deploying multiple virtual machines simultaneously on multiple physical machines is slow due to the inefficient usage of available resources. We implemented and evaluated three methods of transferring virtual machine images for the OpenNebula cloud middleware. One of the implementations was based on BitTorrent and the other two were based on multicast. Our evaluation results showed that the implemented methods were significantly more scalable than the default methods available in OpenNebula when tens of virtual machines were deployed simultaneously. However, the implemented methods were slightly slower than the old ones for deploying only one or a few virtual machines at a time due to overhead related to managing the transfer process. We also evaluated the performance of different virtual machine disk formats, as this choice also affects the deployment time of the machine. Raw images, QCOW2 images and logical volumes were evaluated. Logical volumes were fastest overall in sequential disk I/O performance. With sequential reads and writes, raw images could provide at best approximately 88% of the write performance and 95% of the read performance of logical volumes. The corresponding numbers for QCOW2 were 86% write and 74% read performance. Random access performance between QCOW2 and raw images was nearly identical, but LVM random access performance in our specific benchmark was significantly worse. If the usage pattern of the cloud is such that deploying large batches of virtual machines at once is common, using the new transfer methods will significantly speed up the deployment process and reduce its resource usage. The disk access method should be chosen based on what provides acceptable performance for the task being executed and provides the fastest deployment times.
Improving the process of debugging communication patterns in 5G Layer 1
(2019-10-21) Saarinen, Tommi
Perustieteiden korkeakoulu | Master's thesis
Debugging lower protocol layers in distributed mobile communication systems can be a complicated and a time-consuming task. Although software to inspect communication patterns between network endpoints exist, the process may require a lot of effort from software developers in the form of additional software installation and overall data processing to arrive into conclusions that can actually be used in solving reported faults in base station software and hardware. The primary goal of this thesis is to study the required fault debugging steps from 5G Layer 1 (L1) perspective. Previously, the typical workflow has consisted of acquiring a packet capture containing message exchange between endpoints, parsing it into a readable format and visually inspecting packet contents. Even though expert opinion is always needed in the final evaluation of a reported fault, the current process as a whole includes manual, repetitive and redundant phases that have potential for automation and improved tools. Thus, the priority for this thesis is to design and implement a framework automating these steps to speed up problem solving for L1 faults. Aside from the manual workflow, a lot of subtle faults can easily be missed by sheer human inspection. This thesis additionally discusses the use of graph-based modeling to automatically report discrepancies in communication sequences. This goal is realized in the form of a model checker, which is implemented to locate anomalies in message exchange with strict time constraints. The solution proposed in this thesis reduces the number of necessary debugging steps significantly. It implements relevant software components required to upload, dissect, index and store packet capture data and combines all the components into a software stack. To initiate the debugging sequence, also a clear user interface is included to require minimal effort from the user. The processed data in all its intermediate steps is included in the stack and made easily sharable, which can further reduce the total time spent if several people are included in the process.
Improving the support for ARM in the IgProf profiler
(2014-11-03) Nybäck, Filip
Perustieteiden korkeakoulu | Master's thesis
IgProf is an application profiler that profiles mainly performance and memory usage. The profiler is extended and improved in three ways as part of this thesis: support for 64-bit ARM is implemented, the execution time of stack tracing is reduced on both 64-bit and 32-bit ARM and a simple energy profiling module is added. The IgProf profiler was available on the Intel x86 and x86-64 architectures, as well as on 32-bit ARM, but support for 64-bit ARM was missing. The port of IgProf to 64-bit ARM enables developers to evaluate how applications execute on the new architecture with regard to performance and memory usage. The port of IgProf is going to be used on 64-bit ARM for examination and optimisation of the CMS software, which is related to the Compact Muon Solenoid (CMS) experiment at CERN. IgProf uses the libunwind library to perform stack tracing as part of the profiling. An optimised version of stack tracing, previously available only on the x86-64 architecture, is ported to both 64-bit and 32-bit ARM. The optimised stack tracing reduces the execution time of profiling, especially when profiling events occur frequently. When a piece of CMS software is profiled for memory usage on 64-bit ARM and the optimised version of stack tracing is used instead of the old version, the execution time of profiling is reduced by approximately 87 %. The overhead in execution time of profiling may not matter when a small application is profiled, but for a big application the overhead determines if it is practically feasible to profile the application. A simple energy profiling module extends the functionality of IgProf. The energy profiling module is based on sampling and obtains energy measurements from the Running Average Power Limit (RAPL) interface present on recent Intel processors. The profiling results of a simple single-threaded application seem to show a correlation between the execution time and the energy spent in a function. The energy profiling module is still rather limited, but is the first step for IgProf in the direction of energy profiling.
Mobile video crawler; Implementing a video streaming quality of experience measurement system
(2014) Meyn, Anselm Joseph
Perustieteiden korkeakoulu | Master's thesis
Modelling and implementation issues in circuit and network planning tools
(2003-06-11) Nurminen, Jukka K.
Doctoral dissertation (article-based)
This thesis consists of studies of modelling and implementation issues for planning tool development. In particularly it emphasizes issues that are relevant for practical, industrial use of mathematical models and algorithms. Using a circuit design and a network planning tool as concrete examples the thesis analyses the practical issues of the development and maintenance of such systems and, especially, how models and algorithms affect these. An important part of the thesis is observations of the changes in the software products over time and analysis what effect and requirements the evolution has for the models and algorithms. The thesis deals with implementation in a wide sense. In addition to the issues of the implementation of a given algorithm this work discusses algorithm selection, development process, users' role, software evolution and how these affect each other. In particular the thesis tries to answer three questions: (i) What kind of models and algorithms to use in the tools? (ii) How to divide the work between the computer and the user? (iii) How to develop such tools? The main part of this research has been conducted using the participant observation research methodology by collecting and analysing experiences in the development of two commercial planning tool products. These results have been tied to the model of planning tool implementation that has been developed as part of this work. In particular the focus has been on how technology interacts with tasks, persons, and organizations. The results are also discussed within the context of established research disciplines such as operations research, software engineering, artificial intelligence, and problems solving environments. One finding of this work is the practical significance of simple algorithms and other building blocks that are easy to implement and enhance. This is often more important than high accuracy or strict optimality. The work also suggests a practical way to measure and compare the implementation complexity of algorithms. Another observation is how complex planning tasks should be divided between the computer and human expert. Examples how this is done using knowledge-technology, intelligent interfaces, and different kind of mathematical models are discussed. Practical issues in the development and evolution of algorithms and software are examined in case studies of routing algorithms and of a network visualization software component. These studies highlight the importance of the incremental development approach and discuss its implications to algorithms and software modules.
Personal Information Center(PIC) - A Data Integration Service for the Private Cloud
(2015) Sathi, Rowshan
Perustieteiden korkeakoulu | Master's thesis
Managing information has become an extra load for our everyday life but creating a personal information center (PIC) solves this problem easily. A PIC makes it easier to see content such as email messages, weather information, news items, and even information from local storage by using one view or user interface. Additionally, it fulfills the real world requirements like accessibility, around-the-clock availability of service, and it solves the device constraints problem by creating a common presentation format for all kinds of devices. An importer works spontaneously as a fetcher, parser and processor to process the information to create the nodes content. An analyzer works as an extractor and creates vocabulary terms automatically to auto tag the node content. Finally, a filtering system works for finding similar nodes to create one common presentation with all matched contents. All the works in the PIC is done automatically without any users’ interaction, only the source of information is defined by the users. The analyzer uses machine learning Naive Bayes approach to extract key phrases from the contents. The PIC uses an advanced filtering system to find similarity between nodes and to create a common presentation for all devices.