The Aalto-1 satellite is designed, built and tested mainly by students. The satellite’s subsystems, such as its structure, the on-board computer, software and radio systems, are designed and constructed by students. It is expected to be launched into space in early 2014 on a rocket that will also put a larger satellite in orbit.

Aalto-1 is slightly larger than a milk carton and will weigh only about four kilos. Despite its small size, the satellite will be able to carry a number of research instruments as payload: An imagining spectrometer constructed by VTT, a radiation monitor jointly constructed by the Universities of Helsinki and Turku and a plasma brake designed by the Finnish Meteorological Institute, which is based on the principle of an electric solar sail.

How is a satellite controlled? 

A satellite receives radio commands on the basis of which the ADCS adjusts its orientation. The ADCS must be able to orientate the satellite as required by the on-board scientific measuring instruments and the system must function without hitches so that the measurements can be carried out correctly.

In his thesis, Tikka implemented an ADCS for three-axis stabilized nanosatellites. He created a process that consisted of requirement specification, system selection, procurement, verification and operations. It was tailored for the needs of student satellite projects, which involve a small number of people, are implemented in a short time and can make use of commercial components.

Tikka has valued the degree of freedom that the students have enjoyed when working on the project.

“I was given the chance to select the control system for the satellite. Of course, the decision had to be made within the limits set by the payload. I’m also responsible for ensuring that the system will function properly when the satellite is launched. I must say that I’m a bit nervous,” explains Tikka.

The work on the ADCS and a number of other systems for Aalto-1 are already nearing completion.

“I have visited our ground station that will be used for communicating with the satellite. There I was able to listen to the beeps of the satellites already in space,” recounts Tikka.

"Space is no longer as far away as during moon flights” 

“What fascinates me in space is the fact that it’s so unknown and challenging. It's a totally different environment than the earth and a place that you can still explore,” says Tikka explaining his interest in space.

However, we are learning more and more about space, and space technology is being developed all around the world, including universities. With the Aalto-1 project, students, too, can reach for the orbit.

“At first, building your own satellite sounded an incredible idea. It has been rewarding to see how the idea is becoming more and more real by the day. Before I came here to study, I wouldn’t have thought that one day, I would be able to design something and send it to space.”

Tuomas Tikka graduated from the Degree Programme in Electrical Engineering with space technology as his major subject. Even though Tikka has now completed his studies, he has not given up satellite work as he will continue in the project as a researcher. Tikka’s thesis and the Aalto-1 project will be presented at Masters of Aalto event at Jätkäsaari in Helsinki between 9 May and 3 June 2012.

Text: Anni Aarinen. Photo of Tuomas Tikka: Sofie van Dam. Satellite picture: Aalto-1 project.

More information:

• Information about Tikka’s thesis at the website of Masters of Aalto
• The Master’s thesis in electronic form
• Website of the Aalto-1 project
• Follow the progress of Aalto-1 on Facebook

Nanowires are semiconductors that are approximately 1,000 times thinner than a human hair. In solar cells, their task is to convert solar energy into electricity. This is the first time that researchers have been able to grow high-quality nanowires directly on glass substrates.

According to Professor Harri Lipsanen who led the research project at the School of Electrical Engineering, the research results are currently being developed in order to create a complete solar cell.

“Previously, the growing of high-quality nanowires for solar cells required very expensive wafers,” Lipsanen says.

Glass would be a very low-cost material for solar cells. Project head researcher Dr. Veer Dhaka explains that the nanowires were grown on the same type of glass that is typically seen in household windows.

“Glass-based solar cells would be significantly less expensive than silicon-based ones, for instance. The opportunity to use low-cost materials is just one of the benefits provided by nanowires,” Dhaka says.

Efficient absorption of energy

According to Dhaka, GaAs nanowires grown on semiconductor substrates such as silicon contains  numerous  stacking faults,  and are very poor emitters of light due to high surface defects. In particular, using epitaxial growth techniques, it is extremely difficult to obtain single phase structure of nanowires on semiconductor substrates. In contrast, nanowires grown on glass substrates are of very high optical quality with a single phase zinc blende structure.  

“Solar cells based on radial or axial pn junction nanowires do not require an antireflection coating because the nanowires are able to absorb sunlight so well that absorption losses are not a problem.  In addition, a higher quality can be attained when nanowires are grown on glass instead of a semiconductor substrate.”

Aalto cooperation at its best

The nanowires were grown at the School of Electrical Engineering, but their atomic structure was examined at the Nanomicroscopy Center of the School of Science by Professor Esko I. Kauppinen and Doctor Hua Jiang, Senior Scientist.

“This study is an excellent example of the cooperation between the schools of Aalto University,” Professor Kauppinen says.

“We transferred the nanowires from the glass substrate onto a very thin, holey carbon film. Through the holes, we were able to get an excellent view of the nanowires using an electron microscope. This made it possible to determine the atomic structure of the wires.”

The research project is part of the Nordic NANORDSUN project whose participants include Aalto University and universities from Norway and Sweden.

An article on the research results has been published in the Nano Letters journal:

http://pubs.acs.org/doi/abs/10.1021/nl204314z?prevSearch=veer%2Bdhaka&searchHistoryKey=

Text: Tea Kalska

The list of accepted students can be found here:http://studies.aalto.fi/en/admissions/admissionresults/

Please note that the list contains the names of only those applicants who have given the permission to publish their admission decision on the web pages. 

The applicants can also check their own admission result in the online application system https://apply.aalto.fi. 

A Letter of Acceptance will be sent to the admitted students by mail.

More information: 
Aalto University Admission Services
admissions@aalto.fi

Researchers at Aalto University have managed to find a mechanism that may explain the impaired functionality of laser diodes made of gallium nitride.

Researchers Sami Suihkonen and Henri Nykänen explain that the optical properties of a gallium nitride material deteriorate when treated at a high current density. This also affects laser diodes, as they function at a high current density. The phenomenon is explained by dot defects caused during material manufacture.

"Gallium nitride materials and the layer structures of the components are manufactured through a specific industrial process. We discovered that empty gaps, i.e. dot defects, remain in the atomic lattice during the manufacturing process and easily escape detection", the researchers say.

Hydrogen atoms hide defects

According to the researchers, a laser diode incorporates alloyed gallium nitride layers produced in atmospheric hydrogen. When empty gaps remain between atoms during an industrial manufacturing process, insidious hydrogen atoms fill the gaps and practically neutralise momentarily the effects of the dot defects.

"It is as if the hydrogen atoms hid the dot defects", Suihkonen and Nykänen explain.

The faults appear and start affecting later, however. When the gallium nitride material is treated at a high current density, electrons kick the hydrogen atoms out and prevent them from filling the empty gaps. Consequently, the dot defects are activated and start interrupting the electrical and optical properties of the material.

"This also affects the functionality of laser diodes. Now that the cause of impaired functionality has been discovered, we can start examining ways to modify the manufacturing process to create fewer dot defects."

Chance at play 

Suihkonen and Nykänen reveal that they had not knowingly sought an answer to the impaired functionality of laser diodes. Their suspicions on the cause of this phenomenon were aroused while carrying out a whole different study. The discovery was substantiated through experiments.

"We used a carefully focused electron beam in our tests to concentrate a lot of effect in a limited area. The deterioration of the optical quality of gallium nitride was detected since the electron beam saved us from having to expose the material for thousands of hours; a few minutes sufficed instead."

The new research results attracted a lot of attention when introduced at the Material Research Society conference in San Francisco in April. The article “Low energy beam induced vacancy activation in GaN” written on the results was published in Applied Physics Letter on 21 March 2012. The authors of the article were Henri Nykänen, Sami Suihkonen and Professor Markku Sopanen from the School of Electrical Engineering and Filip Tuomisto and Lukasz Kilanski from the School of Science.

Text: Tea Kalska

Sonic gestures are human-generated actions that produce sound (with the exception of speech) and can convey information. Examples include whistling, stepping sounds or finger snaps.

Sonic gesture applications are based on algorithms that can track the information contained in the gestures from an audio stream fed into a computer. Antti Jylhä presents a new kind of classification for sonic gestures and the information conveyed by them. The classification is beneficial for interactive computer applications when sound is used for information input.

The sound input means that the user does not need to be in eye contact with the computer or control it by touch. Thus, sound input is also suitable for applications developed for the visually disabled and situations in which the eyes have to focus on some other task (such as observing the environment).

Computer as a flamenco teacher

The dissertation included new prototypes for applications utilising sonic gestures. One of these is the virtual flamenco tutor application iPalmas. It can reliably recognise different hand clapping patterns and their tempo. The program presents users with flamenco music clapping rhythms, listens to the clapping sounds produced by the user and provides audiovisual feedback on learning of clapping patterns.

The clapping analysis method can also be applied analysing the sounds of percussive instruments, for example, bongo drums or a tambourine.

Dissertation event

Antti Jylhä's  dissertation takes place at Aalto University School of Electrical Engineering on Friday 20th April 2012 at 12 noon. The title of the thesis is “Sonic Gestures and Rhythmic Interaction between the Human and the Computer”.

For more information:

• Antti Jylhä, tel. +358 40 730 7979, antti.jylha@aalto.fi

"We are looking for ways to improve teaching with the help of information and communication technologies. Robotics is one of the tools of technology education", Tiina Korhonen, Vice Head Master of Koulumestari School, explains. Together with the Learning Center Innokas, the school co-ordinates the Robotti Ruttunen project, which includes schools, universities and other institutes throughout the country.

A pilot study is under way in a couple of Espoo schools. Two Aalto students are involved: Tomi Pieviläinen runs a robot club at Vanttila School, and Matti Leinonen does likewise at Tähtiniitty School.

Sumo wrestling and robot senses 

Hectic preparation for April's RoboCupJunior competition is under way at Vanttila School. The pupils have formed three groups, whose robots compete for Finnish championship titles in sumo wrestling. Each robot fights another in an autonomous manner – when within the sumo ring, the robot is not allowed to be guided or touched.

“How the robot attacks or defends itself is based on the children's ideas. The robot must, among other things, stay within the sumo ring: in other words, it must be able to recognize the border lines of the ring. We program the robot to conform to this kind of requirements”, Tomi explains.

The club of Tähtiniitty School does not participate in the robot competition; thus get-togethers there are more informal.

“In addition to programming and building with Legos, we have familiarized ourselves with various sensors. These function as the robot’s senses on which its operation is based. Programming determines how the robot reacts, for example, to sound or how it estimates distances with the help of ultrasound”, Matti explains.

Learning by playing 

"While playing with robots, children subconsciously learn, as they wonder how the things work", Matti tells.

"Programming teaches one to consider cause-effect relationships: for example, how code modification in a computer program affects a robot's behaviour", Tomi continues.

According to Tiina Korhonen, use of robotics is not limited to natural sciences, but can penetrate all study subjects.

"In these clubs, we can learn inference, group work and problem solving. Also how to perform and how to present one's own work are practiced. As a technology, robotics is a tool and not an end in itself", she explains.

Teaching improvement and pastime activities 

"I want to provide meaningful teaching for the most advanced students. They want to learn things that are more demanding than the time allows in normal hourly-based teaching", Tomi points out.

Tomi and Matti want to provide the children with an opportunity for technology practice.

"In schools and outside them, many different kinds of clubs, for example clubs related to arts or physical exercise, are offered to children. However, availability of pastime activities related to technology or mathematics is very limited", they explain.

"I myself would have liked to attend this kind of club as a child", Matti admits.

Robotti Ruttunen returns the visit to Aalto University on Thursday, the 3rd of May. At the TUAS house (Otaniementie 17) there will be an event where the most advanced robot club members will present their know-how. Also robots built by the Department of Automation and Systems Technology will be there. The event welcomes the staff of Aalto University, students and also all outsiders who are interested in the activities.

Text: Anni Aarinen. Photos: Tähtiniitty pupils, photographer Matti Leinonen

The programme combines field-specific and interdisciplinary mentoring and international networking is also part of this year’s programme.  The application period has already begun and information on applying can be found in AlumniNET.

Student-alumni mentoring improves the working life skills of students, promotes the networking of students and alumni, and increases the sharing of knowledge and skills. In addition to the private meetings between the students and the alumni, an important part of the programme consists of seminars, company visits and thematic meetings in small groups.

All those alumni who have graduated from one of the predecessors of the schools of Aalto University and have been in working life for at least five years can apply to become mentors. Mentee applications are accepted from master’s degree students.

The application period will continue until May 15^th. The programme will continue throughout the academic year 2012-2013.

Long history in mentoring

The mentoring programme has a long history at Aalto University. Student-alumni mentoring has been arranged at the School of Economics since 1999 and at the University of Technology since 2000. The School of Arts, Design and Architecture is taking part in the programme for the first time this autumn.

The students who participated in the mentoring programme in 2011 have praised it for the support it has provided for their future plans. For the alumni, the programme offered an opportunity to challenge their views and established opinions on working life. Here are some comments from last year’s participants:  

 “Mentoring offered me a lot of support and my confidence in the future grew stronger. Now I know what I want to do after graduation.” (mentee 2011)

“Mentoring provided me with useful tips on the challenges of working life and especially on my own well-being at work.” (mentee 2011)

“I learned to look at working life from a wider perspective and my concerns about the future were alleviated.” (mentee 2011)

“The mentoring programme offered me several new contacts and gave me a better understanding of the life students lead and the issues that are currently topical. (mentor 2011)

“My mentee has made me look at things from new perspectives and I have had to/had the opportunity to examine my own opinions and attitudes critically.” (mentor 2011)

“Meeting young people enables you to grow.” (mentor 2011)

Top of the page: A photograph of the 2011 mentoring programme, by Mikko Raskinen.

Heart defects are often associated with a heart murmur, which can be heard with a traditional stethoscope. A heart murmur is an important indicator in diagnosing heart defects. Most heart murmurs which occur in children are harmless and are not caused by a clinically significant heart disease. Identifying heart murmurs requires experience. It is for this reason that the diagnosis of heart murmurs in children is challenging for conventional medical practices.

In the thesis a prototype system for analysing heart murmurs which was already developed in the late 1990s is presented. The most recent clinical trial results were published in the late 2000s.  For analysis the most common sounds of heart murmurs in children were collated, utilising sources such as the Duodecim Medical Publications Ltd. databases.

Example graphs from the system

	Ideal cardiovascular sound in graph form. S1 and S2 are the sounds caused by the closing of the heart valves, which sounds like the pronunciation of the American tennis term, "DUNN-LOP DUNN-LOP DUNN-LOP, ...". SM is a murmur caused by normal heart action, which can be easily confused with pathological sounds. This could be voiced aloud as, "DUNN-R-LOP DUNN-R-LOP, ...".
	Harmless murmur registered in a healthy child. The sounds of the valves closing are clearly visible. Between them a harmless murmur (SM) can also be seen. At the bottom of the picture is a pitch map. The vertical axis represents frequency (0-1000 Hz), while the horizontal axis shows the volume. A powerful sound is shown in red and the background is blue. From this picture we can see that a harmless heart murmur only lasts a moment and it does not have high frequencies.
	VSD (Ventricular septal Defect) is one of the most common heart defects in children. In this case there is a gap between the heart chambers, and the blood can flow between the right and left chambers. This results in a murmur, which is generally much longer than in normal cases. Similarly in the colour chart below, the strong yellow and green hues can be seen in extending into the higher frequencies.

Once the duration and height of the heart murmur are measured on these graphs it can be determined whether the heart is normal or requires treatment. In normal cases the duration of the heart murmur is shorter and the height of the murmur is lower than in pathological situations.

Dissertation event

Sakari Lukkarinen's dissertation takes place at Aalto University School of Electrical Engineering on Friday 13th April 2012 at 12 noon. The title of the thesis is “Phonocardiography: Development of a clinical system and its application to screening for paediatric heart murmurs”.

For more information:

• Dissertation event
• Sakari Lukkarinen, tel. +358 40 900 4952, sakari.lukkarinen@metropolia.fi

Ater Amogpai arrived in Mikkeli, Finland from Cairo in 2002. He had been studying in Khartoum but the civil war in Sudan forced him to flee the city and move to the Egyptian capital.

“When I was told that I could try and go to Finland, I knew nothing about the country.  I left for Finland when I heard that I might be able to continue my studies there and that Finland had free education.  I was warmly received in Mikkeli and I liked the place,” explains Amogpai in the foyer of the well lit School of Electrical Engineering.

“After a few years I found myself in Otaniemi, writing my dissertation as a member of the lighting research team of Liisa Halonen.”

One third of the people without electricity

Sudan and particularly South Sudan, the region where he was born, was constantly in Amogpai’s thoughts as the country was often in the headlines. The civil war that had started in 1983 and had claimed 1.5 million lives came to an end in 2005 and South Sudan finally gained independence in July 2011.

“As early as 2005, Professor Halonen suggested that I should select South Sudan as the topic of my research and it was clear that I would focus on energy-saving LEDs, which Halonen had already studied,” recounts Amogpai.

The International Energy Agency IEA has estimated that 1.4 billion people (29% of the world’s population) are still without electricity. The number of people without electricity is highest in Sub-Saharan Africa. About 60% of the people living in cities and towns have access to electricity, while the figure in rural areas is only 14%.

Kerosene lamps and firewood emitting unhealthy combustion gases are a common source of light and energy in South Sudan and many of its neighbours. Poor transport connections, difficult terrain and the vast amount of solar radiation in the Equator mean that solar panels are potentially an excellent way of generating energy in the region.

Providing South Sudan with light

In his study, Amogpai collected comparative data on how LED lighting can be combined with solar panels in different geographical conditions in equatorial Africa. At the same time, his aim was to determine the differences between solar panel systems and to find the systems that are best suited for lighting generation. He also compared the use and cost of solar panels and diesel generators.

The results show that introducing solar panels in Sudan would pose no problems as there is sunlight all year round and that energy-saving LEDs would be the best option for lighting. 

In fact, South Sudan is facing a situation where it will make a leap from kerosene lamps to LEDs operated with solar panels and skip the era of light bulbs altogether. The country still has substantial oil resources but it is estimated that the production will peak this year. This means that new solutions for energy generation are badly needed. 

With his study, Amogpai has produced an information package on new lighting technology for developing countries and a document that can persuade his compatriots in South Sudan to choose the latest energy and lighting technologies as engines for regional development. 

Equipped with a dissertation and lots of good wishes, Amogpai will soon return home after a long absence. He plans to set up a business or a research unit of his own for disseminating information about LED lighting and solar panels. 

Ater Amogpai´s dissertation took place at Aalto University School of Electrical Engineering on Friday 25th of November at 12 pm. The title of the thesis is "LED lighting combined with solar panels in developing countries"

Text: Eeva Pitkälä. Photo: Laura Nissinen.

In his doctoral dissertation, Jari Nieminen presents a new, multi-channel protocol that shares the transmission media among sensor nodes and avoids collisions of transmissions. The protocol was designed to correspond with the requirements of wireless sensor network applications. It also outperforms other existing solutions with respect to delay. Minimising delay is crucial in delay sensitive applications, including wireless automation and target tracking.

Using wireless sensor networks in sensor applications to replace fixed connections brings new challenges en route to the large-scale use of wireless systems in sensor networks, the most important ones of which include improving robustness and efficiency together with minimization of communication delays.

Wireless sensor networks consist of sensor nodes that measure the environment, and one or several gateway nodes that collect the wirelessly sent information from sensor nodes. They represent an interesting solution for numerous applications, as they are free from the constraints of cables, while other advantages include low installation costs, flexibility and ease of maintenance.

Jari Nieminen´s dissertation takes place at Aalto University School of Electrical Engineering on Wednesday 30th March 2012 at 12 noon. The title of the thesis is “Media Access Control and Time Synchronization in Delay-Sensitive Multi-Channel Wireless Sensor Networks”.

More information:

• Dissertation event
• Electronic dissertation thesis
• Jari Nieminen, tel. 09 470 25686, jari.nieminen@aalto.fi

Using electric cars requires planning

In summer conditions an electric car’s fully charged battery will last for a journey of 100 km. However, during winter, part of its energy is used for heating the vehicle. An electric car’s operating radius, i.e. the distance it can travel on a certain amount of energy, is a key aspect in creating a well functioning charging system.

There will be a need for a large number of electric car charging points. Drivers must have easy access, for example via the internet or mobile services, to information about the location and capacity of charging points.

“Charging a battery to 80% of its operating capacity takes approximately 20 minutes with fast-charge. Service stations must be equipped with a sufficient number of fast-charge points, to ensure that vehicles need not wait in line, while others are charging their batteries to full capacity,” explains Professor Matti Lehtonen from the Department of Electrical Engineering.

One of the greatest advantages of electric transportation, from a town resident’s perspective, is that electric cars do not produce local emissions. Smoking exhaust pipes would be a thing of the past. The electricity used by cars could be produced in a way that is as environmentally-friendly as possible. This would improve both the air quality in towns and the well-being of town residents.

“On the other hand, on a journey from Helsinki to Utsjoki an electric car would need to be charged some ten times per direction. Charging intervals during long trips would need to be planned carefully,” Professor Lehtonen observes.

Electric cars are best suited for travelling short distances. A sufficient number of users would be required in towns to ensure that charging points could be situated at close intervals. Slow charging points would be needed anywhere where electric cars are parked: parking garages, homes, and workplace parking spots.

Charging system needs a business framework

Investments must be made in the infrastructure required by electric cars, especially in charging points. Electricity sockets currently used for heating cars in winter may need to be renewed so that they can carry the heavier load required for charging an electric car.

New businesses will be needed in the field to offer services throughout Finland for charging electric cars, irrespective of limits set by electricity companies.

Charging points would also need be equipped with intelligence, so that they could process payments for charging. 

“With all probability, we will first have a system where users are charged a small fee each time they plug their vehicle into a public charging point. Residents of multi-family buildings and single homes, who use electric vehicles, could then acquire their own charging points for their property," Professor Lehtonen surmises.

Electric cars as electricity stores

As production of wind and solar energy fluctuates according to conditions, a reserve capacity is required at times when there are disturbances in supply. The research project envisions a situation in which electric cars and the electric power system could support and supplement one another.

“If electric cars one day become the leading form of transport, batteries of parked cars could act as convenient energy storage points, for those times when the wind is not blowing or the sun is not shining," suggests Professor Lehtonen.

A car’s battery would be charged outside of electrical consumption peaks, for example at night time when electricity tariffs are lower. When a car is not in traffic, its owner could then make a profit by selling electricity back into the network, when demand for electricity and therefore its price are higher. Trade of electricity could happen via smart charging points.

“The project is looking into the type of legislation required to make this possible as well as into ways in which a charging system operator could make the process as simple as possible for electric car owners,” Professor Lehtonen details.

Text: Anni Aarinen

More information:

• Website of the Electric Traffic project
• Eco Urban Living program develops Espoo into an eco-sustainable city
• Electric cars where tested in a temperature of -20 below cero – check out the video on YouTube
• Filling up with electricity [sci.aalto.fi]

He became interested in working in Aalto University once he heard about an open position in the context of the Communications Ecosystem master’s programme, which has an interdisciplinary environment.

“I believe this course is quite unique, at least in Europe”, Reichl says.

Holistic perspective on telecommunication ecosystems

Reichl’s research field could be described as ‘future telecommunication ecosystems’. In an ecosystem, various types of business and private customers communicate with each other using a sophisticated technological infrastructure including networks and service platforms.

“Traditional research in telecommunications has focused pretty much on the technological side. However, along with several colleagues from Aalto, I aim at a more holistic perspective on such systems. This makes research in the field an inherently interdisciplinary activity, bringing together economics and social sciences with electrical engineering, computer science, and end user research”, he explains.

Striving for fruitful collaboration

“After several years of research in a more industry-oriented context, I am looking forward to entering the academic environment again. I believe Aalto University is a very good place for this endeavour. It will be possible to shape and follow creative and unconventional ideas in a truly interdisciplinary way.”

Reichl hopes to get to condense joint scientific interests into concrete projects and activities. Simultaneously, he also hopes to both maintain his current international research cooperations, and to explore collaboration opportunities with industry partners in Finland and Scandinavia.

“Interesting frameworks for collaboration between my current partners and Aalto already exist – for example, Aalto is a member of the EIT ICT Labs Helsinki node. I plan to be very active in further developing these European links.”

Heikki Ihasalo’s tool presents data visually so that maintenance teams, for example, can use it in their day to day work. Property and facilities managers can use visual data as an aid when managing maintenance at properties. 

The objective is to avoid quality problems, particularly in the low energy buildings of the future which will be technically more complex than today’s properties.

"Increasingly tough energy efficiency requirements will generate a variety of challenges: for example, reducing energy consumption without impacting on the quality of internal air is difficult", Ihasalo explains.

Heikki Ihasalo's dissertation takes place at Aalto University School of Electrical Engineering on Friday 23rd March 2012 at 12 noon. The title of the thesis is “Transforming building automation data into building performance metrics – design, implementation and evaluation of use of a performance monitoring and management system”.

For more information:

• Dissertation event
• Electronic dissertation thesis
• Heikki Ihasalo, tel. +358 40 820 9623, heikki.ihasalo@gmail.com

“In spite of the smartphone boom, only about half of mobile phones in use today support 3G networks, and one third support WLAN or GPS. For example, it will still take years for these features to become common in 80-90% of the phones in Finland”, Smura explains.

The average time in service for a mobile phone in Finland is about 2.5 years, during which time the phone may be used by one or more owners. Some users obtain a new phones at a considerably slower rate – thus about one fifth of the active stock of devices is more than four years old.

Since only a portion of new equipment is smartphones with advanced features, proliferation of essential features in terms of new networks and services will take time.

Diffusion of new product features can be predicted

As a part of his dissertation, Smura developed a novel way of predicting the diffusion of new product features in mobile equipment and other similar technology products. By using this method it is easier, for example, to estimate, how changes in markets affect trends in a mobile equipment base.

“Improved forecasting of trends in a mobile equipment base makes it possible for operators to optimize network investment plans in a timely manner. Similarly, developers of services can have more realistic expectations as to the size of achievable market”, Smura sums it up.  

The method combines known and unknown factors: known diffusion models at a product category level and substitution models at a product unit level are combined with the phenomenon of diffusion of product features, which has not been investigated before.

Serving as a backdrop to the model and forecasting is material, totally unique in the word, collected from 2005–2011 about mobile phone models in use as well as their total sales figures and features.

Timo Smura's  dissertation takes place at Aalto University School of Electrical Engineering on Friday 23rd March 2012 at 12 noon. The title of the thesis is “Techno-economic modelling of wireless network and industry architectures”.

More information:

• Väitöstilaisuus
• Electronic dissertation thesis
• Timo Smura, tel. +358 50 536 9855, timo.smura@aalto.fi

Seven students from the Olari, Tapiola and Pohjois-Tapiola high schools attended the four-day course, which included diverse lectures on the construction, operation and tasks of satellites. The programme also included visits to the Finnish Meteorological Institute’s Laboratory of Space Technology, the ground station of the Aalto-1 satellite and the Metsähovi Radio Observatory.

“I expected a fairly theoretical course, so I was thrilled to see that the course outline also included laboratory work. On the other hand, it was great to attend lectures given by a real expert in the field,” says course participant Esteri Viitanen. She is in her first year at Pohjois-Tapiola High School.

Building a satellite prototype antenna from drinking straws

The students received a thorough introduction to the Aalto-1 student project, which involves students building Finland’s first satellite.  Inspired by this work, the students spent the third afternoon of the course at a satellite workshop, where they designed their own satellite and built a prototype.

The design had to take into consideration all satellite sub-systems – from communications to energy production. They also had to plan an assignment for the satellite: what kind of research device would the satellite become and what jobs could it perform? The construction material provided for building the prototype included everything from circuit boards to drinking straws.

The students weren't just tinkering around: their goal was to participate in an international satellite mission competition where they would test their ideas against satellite projects developed by university students and others with an interest in the field.

Future space technology professionals?

The lessons clearly hit home: while immersed in their design work, the students fluently debated how the satellite’s sensitive electronics could be protected from gamma radiation and what kind of heat insulation would be needed. The high school students threw out ambitious ideas about, for example, cold nozzles that would adjust the flying altitude of the satellite while it orbited the Earth.

One matriculation candidate attending the course has already been accepted at the School of Electrical Engineering for next autumn. Perhaps one of the other students will find him or herself studying space technology in the future, as well.

Text: Anni Aarinen. Photos: Tuomas Tikka.

More information:

• LUMA Resource Centre at Aalto University
• Aalto-1 student satellite project
• Satellite mission idea contest

Often large material flows are subjected to the mineral concentration process. For this reason, even small improvements in the process efficiency are significant.

– An improvement of one per cent in the extraction of a valuable mineral is all that is needed to see, on an annual level, a directly proportional increase in the financial result of the production unit through the concentration plant's ore feed and world market price, Remes clarifies.

Remes discussed monitor and control processes in certain mineral concentrator's unit processes and processing circuits. The doctoral dissertation examined advanced control systems with the help of simulated grinding and flotation processes.  Included were the rule-based control, fuzzy control and model predictive control. In addition, several concentrator unit processes were modelled in the dissertation.

All the methods developed in this work were tested with industrial data, using industrial process models or practical process tests, or by implementing the methods at the concentration plant. The processing targets were mineral grinding, flotation, specific weight separation and thickening.

In the dissertation several already established methods were further developed by combining them in a novel way and by applying them to new mineral processing targets. With this, answers were sought regarding the practicality of the methods, limitations required by them, as well as the best ways to implement them.

Antti Remes´s dissertation takes place at Aalto University School of Electrical Engineering on Friday 16th March 2012 at 12 noon. The title of the thesis is “Advanced Process Monitoring and Control Methods in Mineral Processing Applications”.

Electronic dissertation thesis

Dissertation event

More information:

Antti Remes
Tel. +358 40 5373670
antti.remes@outotec.com

Information about underwater noise levels are needed for performance calculation values for various forms of underwater listening, sonar and communications systems. The study results will primarily be used for performance optimisation for different kinds of underwater acoustic systems.

The measurements can also be used to determine the natural range underwater noise, which can be used for example in assessing sounds within hearing distances of marine mammals or the effects of man-made underwater noise on marine life.

In the bubble model used in his thesis Ari Poikonen numerically demonstrated for the first time a link between the typical noise spectral slope S ~ 1/f2 and seawater bubble size distribution n(a) ~ 1/a(3/2).

Wind-induced underwater noise in the Gulf of Finland was studied in shallow brackish waters over a wide frequency range. The aim was to obtain systematic information about the level of noise and its properties. Noise measurements were carried out in all seasons, but temporal dependence was not observed in the noise levels.

Dissertation

Ari Poikonen's dissertation takes place at Aalto University School of Electrical Engineering on Friday 9th March 2012 at 12 noon in room S1 (Otakaari 5A, Espoo). The title of the thesis is “Measurements, analysis and modeling of wind-driven ambient noise in shallow brackish water”.

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• Disseration event
• Electronic dissertation thesis (otalib.aalto.fi)
• Ari Poikonen, tel. 040 744 6977, ari.poikonen@kolumbus.fi

More information:

Chia-Hao Yu,
tel. +88 693 377 1177
elicyu@gmail.com

HECL is a relatively new analysis method and Niskanen’s doctoral dissertation examines how suitable various materials and production methods are for the electrodes that are used to produce hot electrons in the solution being examined. Niskanen also developed an integrated, single-use sensor component that facilitates and accelerates the analysis.

Microfabricated gas sensors are commonly used to detect toxic gases near processes or equipment that require the use of such gases, in the environment and at accident scenes. Niskanen’s doctoral dissertation examines the use of atomic layer deposited (ALD) thin films in microfabricated gas sensors. ALD enables the deposition of various thin film materials and material combinations, but requires certain changes to the fabrication process of the sensors. Based on the components produced using the new process, the ALD films were found suitable for this purpose. The new process can be a less expensive way of fabricating gas sensors since a larger number of the production phases are performed on silicon wafers instead of on individual components.

Chemical sensors are needed in analysis laboratories and production facilities, but also in health care, environmental protection and the monitoring of personal safety. In many of these applications the small size of the analysing device, a small amount of sample required, and an inexpensive price are desirable properties.This is why the microfabrication methods developed for the needs of microelectronics are also used in the production of chemical sensors.

M.Sc. Antti J.Niskanen’s doctoral dissertation ”Thin film technology for chemical sensors” will be publicly examined at 12 noon on 27 January 2012 at the Aalto University School of Electrical Engineering in the Micronova large lecture hall (Tietotie 3, Espoo).

More information about dissertation

More information:

Antti J. Niskanen
tel. 050 309 9114,
Antti.Niskanen@iki.fi

Periodicity is an important feature in speech communication. It is based on the vibration of the vocal folds and can be heard as the voiced nature and pitch of speech sounds. The transfer of information from speaker to listener is a process that includes the activities of the speech organs, the transferral of the speech signal in the medium and the neural processing of the speech from the labyrinthine fistula to the cerebral cortex. Therefore, research on the cerebral mechanisms related to speech requires a multidisciplinary approach.

In this research project, the periodicity of speech sounds was manipulated by using acoustic speech modelling and the brain activity elicited by these stimuli was measured using magnetoencephalography (MEG). MEG is a technique for mapping brain activity by measuring magnetic fields produced by electrical currents occurring in the brain.

Santeri Yrttiaho’s doctoral dissertation ”Cortical processing of the periodicity of speech sounds” will be publicly examined at 12 noon on 20 January 2012 at the Aalto University School of Electrical Engineering in lecture hall S1 (Otakaari 5 A, Espoo).

Electronic dissertation (pdf)

More information:

Santeri Yrttiaho
tel. +358 50 301 5246
santeri.yrttiaho@aalto.fi