Browsing by Department "University of Oulu"
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- Analysis of airport design for introducing infrastructure for autonomous drones
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä(2023) Edelman, Harry; Stenroos, Joel; Peña Queralta, Jorge; Hästbacka, David; Oksanen, Jani; Westerlund, Tomi; Röning, JuhaPurpose: Connecting autonomous drones to ground operations and services is a prerequisite for the adoption of scalable and sustainable drone services in the built environment. Despite the rapid advance in the field of autonomous drones, the development of ground infrastructure has received less attention. Contemporary airport design offers potential solutions for the infrastructure serving autonomous drone services. To that end, this paper aims to construct a framework for connecting air and ground operations for autonomous drone services. Furthermore, the paper defines the minimum facilities needed to support unmanned aerial vehicles for autonomous logistics and the collection of aerial data. Design/methodology/approach: The paper reviews the state-of-the-art in airport design literature as the basis for analysing the guidelines of manned aviation applicable to the development of ground infrastructure for autonomous drone services. Socio-technical system analysis was used for identifying the service needs ofdrones. Findings: The key findings are functional modularity based on the principles of airport design applies to micro-airports and modular service functions can be connected efficiently with an autonomous ground handling system in a sustainable manner addressing the concerns on maintenance, reliability and lifecycle. Research limitations/implications: As the study was limited to the airport design literature findings, the evolution of solutions may provide features supporting deviating approaches. The role of autonomy and cloud-based service processes are quintessentially different from the conventional airport design and are likely to impact real-life solutions as the area of future research. Practical implications: The findings of this study provided a framework for establishing the connection between the airside and the landside for the operations of autonomous aerial services. The lack of such framework and ground infrastructure has hindered the large-scale adoption and easy-to-use solutions for sustainable logistics and aerial data collection for decision-making in the built environment. Social implications: The evolution of future autonomous aerial services should be accessible to all users, “democratising” the use of drones. The data collected by drones should comply with the privacy-preserving use of the data. The proposed ground infrastructure can contribute to offloading, storing and handling aerial data to support drone services’ acceptability. Originality/value: To the best of the authors’ knowledge, the paper describes the first design framework for creating a design concept for a modular and autonomous micro-airport system for unmanned aviation based on the applied functions of full-size conventional airports. - Bihelical Spectrum of Solar Magnetic Helicity and Its Evolution
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä(2018-08-20) Singh, Nishant K.; Käpylä, Maarit J.; Brandenburg, Axel; Käpylä, Petri J.; Lagg, Andreas; Virtanen, IlpoUsing a recently developed two-scale formalism to determine the magnetic helicity spectrum, we analyze synoptic vector magnetograms built with data from the Vector Spectromagnetograph instrument on the Synoptic Optical Long-term Investigations of the Sun telescope during 2010 January-2016 July. In contrast to an earlier study using only three Carrington rotations (CRs), our analysis includes 74 synoptic CR maps. We recover here bihelical spectra at different phases of solar cycle 24, where the net magnetic helicity in the majority of the data is consistent with a large-scale dynamo with helical turbulence operating in the Sun. More than 20% of the analyzed maps, however, show violations of the expected sign rule. - Challenging the invisibility of mobile cultures remote sensing, environment and archaeology in the near east
Conference article(2019-05-04) Silver, M.; Törmä, M.; Silver, K.; Nuñez, M.; Okkonen, J.Remote sensing has provided a modern wider perspective to approach the earth with its various environments and impact of humans by prospecting previously unknown frontiers of human life. The traces of mobile groups are archaeologically often more difficult to detect than those of the sedentary ones, but new approaches and methods have changed and enhanced the ways to extract archaeological information of hunter-gatherers and pastoral nomads. Remote sensing, for example, provides alternative views from above and better visibility in a larger scale, especially with high resolution solutions, than on the ground to trace sites. Mobile people have become more visible in archaeology, and therefore their importance in the development of human cultures has received more focus and understanding. This paper will focus on the use of remote sensing in the archaeological study of mobile cultures and their environments in the Near East. Various examples of techniques and site types will be discussed, and the suitability ofapplications will be considered based on the studies by Finnish and Finnish-Swedish projects in the Near East. We will provide examples of applications and emphasize the importance of empirical approaches in studying archaeological evidence by remote sensing. GPS coordinate points have served as the basis of our field survey and mapping. From the image-based data we shall deal with aerial photographs, CORONA satellite photographs, Landsat, SPOT, QuickBird and GeoEye satellite images. From the range-based data we shall discuss X-SAR Shuttle Mission 2000 and ASTER-DEM data, but LiDAR and geophysical devices will only be briefly considered. - A comparative study of creation of self-brand connection amongst well-liked, new, and unfavorable brands
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä(2018-11-01) Tan, Teck Ming; Salo, Jari; Juntunen, Jouni; Kumar, AshishBrand managers are wary of consumers who are either unaware of new brands or have an unfavorable attitude toward their brands. In this study, we investigate the creation of a self-brand connection with new and unfavorable brands in comparison to well-liked brands. Our empirical study reveals that consumers could form a self-brand connection with new and unfavorable brands when the brand serves as a self-presentational strategy—self-presentation by brand. In particular, first, we find that brand attitude predicts self-brand connection positively and significantly for a well-liked brand, but not for a new brand, and second, when consumers hold favorable (unfavorable) attitudes toward a familiar brand, the self-brand connection can exist (be diluted). Thus, the self-brand connection can vary depending upon consumers’ favorability toward the brand. The current study suggests that one-on-one marketing, including customization and personalization, is relevant to new and unfavorable brands. - Delivery of agents into articular cartilage with electric spark-induced sound waves
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä(2018-10-16) Pérez, Alejandro García; Nieminen, Heikki J.; Finnilä, Mikko; Salmi, Ari; Pritzker, Kenneth P.H.; Lampsijärvi, Eetu; Paulin, Tor; Airaksinen, Anu J.; Saarakkala, Simo; Hæggström, EdwardLocalized delivery of drugs into articular cartilage (AC) may facilitate the development of novel therapies to treat osteoarthritis (OA). We investigated the potential of spark-gap-generated sound to deliver a drug surrogate, i.e., methylene blue (MB), into AC. In vitro experiments exposed bovine AC samples to either simultaneous sonication and immersion in MB (Treatment 1; n = 10), immersion in MB after sonication (Control 1; n = 10), solely immersion in MB (Control 2; n = 10), or neither sonication nor immersion in MB (Control 3; n = 10). The sonication protocol consisted of 1,000 spark-gap -generated pulses. Delivery of MB into AC was estimated from optical absorbance in transmission light microscopy. Optical absorbance was significantly greater in the treatment group up to 900 μm depth from AC surface as compared to all controls. Field emission scanning electron microscopy (FESEM), histological analysis, and digital densitometry (DD) of sonicated (n = 6) and non-sonicated (n = 6) samples showed no evidence of sonication-induced changes in proteoglycan content or collagen structure. Consequently, spark-gap -generated sound may offer a solution for localized drug delivery into AC in a non-destructive fashion. Further research on this method may contribute to OA drug therapies. - Ethnic discrimination during wartime : Evidence from a field experiment in the Finnish housing market
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä(2023-12) Mourelatos, Evangelos; Oikarinen, EliasThis paper presents a field experiment studying possible discrimination against Russians in the rental housing market in Finland. We study the effect of discriminatory behaviour by the landlords during the Russian war of aggression in Ukraine, an event that has shaped ideas, attitudes, and behaviour. We let three fictitious individuals, one Finnish, one Russian and one British, apply for vacant rental apartments advertised by landlords on the internet. We then investigated whether there were differences between the individuals in the number of callbacks received and positive invitations to further contact. Linear probability models revealed strong evidence of differential treatment of Russians by Finnish landlords. The discriminatory behaviour is mainly driven by male, private landlords. The present study extends the literature on discrimination in the rental housing market and provides insights into its mechanisms. - Guest Editorial
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä(2022-02) Särkkä, Simo; Roininen, Lassi; Kok, Manon; Hostettler, Roland; Hauptmann, Andreas - Industry 4.0 in Finland: Towards Twin Transition
A3 Kirjan tai muun kokoomateoksen osa(2022) Khan, Iqra; Kauppila, Osmo; Majava, Jukka; Jurmu, Marko; Blech, Jan Olaf; Annanperä, Elina; Jurvansuu, Marko; Pirttikangas, SusannaIn the global rankings of digitalisation and Industry 4.0 maturity, Finland constantly places among the frontrunners. This study examines the path Finland has taken to reach the forefront, the drivers, and the current challenges and future opportunities related to Industry 4.0 and digitalisation. This analysis is based on extensive experience in Industry 4.0-related ecosystem projects, policy documentation and previous research. As Finland focuses on the export of high-value-added products and services, the early adoption of new technologies is vital and thus a key driver. Moreover, the national culture of innovation, R&D and triple helix collaboration have driven Industry 4.0 implementation alongside a highly skilled workforce. However, multiple barriers hindering full Industry 4.0 utilisation still exist, including SMEs’ hesitation to digitalise due to insufficient support mechanisms, an aging population and the difficulty in finding single-source solutions. Respective future opportunities were found in areas such as smart sustainable manufacturing and ecosystems, enhanced SME involvement, lifelong learning and platform economy. Currently, Finland is moving from digitalisation towards a twin transition and sustainable ecosystem-to-ecosystem collaboration. Practical early-stage examples of implementing this policy include the AI 4.0 and the Sustainable Industry X supercluster initiatives. - Main Clinical Use of Additive Manufacturing (Three-Dimensional Printing) in Finland Restricted to the Head and Neck Area in 2016–2017
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä(2020-06-01) Pettersson, A. B.V.; Salmi, M.; Vallittu, Pekka; Serlo, W.; Tuomi, J.; Mäkitie, A. A.Background and Aims: Additive manufacturing or three-dimensional printing is a novel production methodology for producing patient-specific models, medical aids, tools, and implants. However, the clinical impact of this technology is unknown. In this study, we sought to characterize the clinical adoption of medical additive manufacturing in Finland in 2016–2017. We focused on non-dental usage at university hospitals. Materials and Methods: A questionnaire containing five questions was sent by email to all operative, radiologic, and oncologic departments of all university hospitals in Finland. Respondents who reported extensive use of medical additive manufacturing were contacted with additional, personalized questions. Results: Of the 115 questionnaires sent, 58 received answers. Of the responders, 41% identified as non-users, including all general/gastrointestinal (GI) and vascular surgeons, urologists, and gynecologists; 23% identified as experimenters or previous users; and 36% identified as heavy users. Usage was concentrated around the head area by various specialties (neurosurgical, craniomaxillofacial, ear, nose and throat diseases (ENT), plastic surgery). Applications included repair of cranial vault defects and malformations, surgical oncology, trauma, and cleft palate reconstruction. Some routine usage was also reported in orthopedics. In addition to these patient-specific uses, we identified several off-the-shelf medical components that were produced by additive manufacturing, while some important patient-specific components were produced by traditional methodologies such as milling. Conclusion: During 2016–2017, medical additive manufacturing in Finland was routinely used at university hospitals for several applications in the head area. Outside of this area, usage was much less common. Future research should include all patient-specific products created by a computer-aided design/manufacture workflow from imaging data, instead of concentrating on the production methodology. - Making room to manoeuvre: How firms increase their influence with others in business networks
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä(2020-11) Ahola, Tuomas; Aaltonen, K.; Artto, Karlos; Lehtinen, JereEarlier research has highlighted the dynamic nature of influencing in business networks, and shown that firms may vary considerably in their influence, defined as their potential to achieve changes in the activities, resources, or goals of other firms in the business network. There is, however, limited understanding of the specific means of influencing which may allow firms, over time, to increase their influence with other firms in the same network. Drawing on a longitudinal case study, we describe how a firm, through influencing others by the dynamic enactment of network management activities, gradually increased its influence with other firms in the business network. Based on our observations, we offer a processual model for influencing in business networks that links specific network management activities to conditions under which they are used. - Micro-scale distribution of CA4+ in ex vivo human articular cartilage detected with contrast-enhanced micro-computed tomography imaging
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä(2017-08-31) Karhula, Sakari S.; Finnilä, Mikko A.; Freedman, Jonathan D.; Kauppinen, Sami; Valkealahti, Maarit; Lehenkari, Petri; Pritzker, Kenneth P.H.; Nieminen, Heikki J.; Snyder, Brian D.; Grinstaff, Mark W.; Saarakkala, SimoContrast-enhanced micro-computed tomography (CEμCT) with cationic and anionic contrast agents reveals glycosaminoglycan (GAG) content and distribution in articular cartilage (AC). The advantage of using cationic stains (e.g., CA4+) compared to anionic stains (e.g., Hexabrix®), is that it distributes proportionally with GAGs, while anionic stain distribution in AC is inversely proportional to the GAG content. To date, studies using cationic stains have been conducted with sufficient resolution to study its distributions on the macro-scale, but with insufficient resolution to study its distributions on the micro-scale. Therefore, it is not known whether the cationic contrast agents accumulate in extra/pericellular matrix and if they interact with chondrocytes. The insufficient resolution has also prevented to answer the question whether CA4+ accumulation in chondrons could lead to an erroneous quantification of GAG distribution with low-resolution μCT setups. In this study, we use high-resolution μCT to investigate whether CA4+ accumulates in chondrocytes, and further, to determine whether it affects the low-resolution ex vivo μCT studies of CA4+ stained human AC with varying degree of osteoarthritis. Human osteochondral samples were immersed in three different concentrations of CA4+ (3 mgI/ml, 6 mgI/ml, and 24 mgI/ml) and imaged with high-resolution μCT at several timepoints. Different uptake diffusion profiles of CA4+ were observed between the segmented chondrons and the rest of the tissue. While the X-ray -detected CA4+ concentration in chondrons was greater than in the rest of the AC, its contribution to the uptake into the whole tissue was negligible and in line with macro-scale GAG content detected from histology. The efficient uptake of CA4+ into chondrons and surrounding territorial matrix can be explained by the micro-scale distribution of GAG content. CA4+ uptake in chondrons occurred regardless of the progression stage of osteoarthritis in the samples and the relative difference between the interterritorial matrix and segmented chondron area was less than 4%. To conclude, our results suggest that GAG quantification with CEμCT is not affected by the chondron uptake of CA4+. This further confirms the use of CA4+ for macro-scale assessment of GAG throughout the AC, and highlight the capability of studying chondron properties in 3D at the micro scale. - Mirror twin boundaries in WSe2 induced by vanadium doping
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä(2023-06) Pathirage, V.; Lasek, K.; Krasheninnikov, A. V.; Komsa, H. P.; Batzill, M.Mirror twin boundaries (MTBs) observed in MoSe2 are formed due to incorporation of excess Mo into the lattice. In contrast, MTBs in WSe2 have a high formation energy and consequently are not present in this system. Here we show that V-doping of WSe2, achieved by co-deposition of V and W during molecular beam epitaxy (MBE) growth of WSe2, can also induce MTB formation in WSe2, as revealed by scanning tunneling microscopy. Our experimental results are supported by density functional theory calculations that show that V-doped WSe2 is susceptible to the incorporation of more V-atoms at interstitial sites. This increases the transition metal atom concentration in the lattice, and these excess atoms rearrange into MTBs, which is associated with energy lowering of the excess metal atoms. While formation of MTBs gives rise to the pinning of the Fermi-level and thus prevents V-induced electronic doping, MTBs do not appear to affect the magnetic properties, and a diluted ferromagnetic material is observed for low V-doping levels, as reported previously for V-doped WSe2. - Online Non-Cooperative Radar Emitter Classification from Evolving and Imbalanced Pulse Streams
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä(2020-07-15) Sui, Jinping; Liu, Zhen; Liu, Li; Peng, Bo; Liu, Tianpeng; Li, XiangRecent research treats radar emitter classification (REC) problems as typical closed-set classification problems, i.e., assuming all radar emitters are cooperative and their pulses can be pre-obtained for training the classifiers. However, such overly ideal assumptions have made it difficult to fit real-world REC problems into such restricted models. In this paper, to achieve online REC in a more realistic way, we convert the online REC problem into dynamically performing subspace clustering on pulse streams. Meanwhile, the pulse streams have evolving and imbalanced properties which are mainly caused by the existence of the non-cooperative emitters. Specifically, a novel data stream clustering (DSC) algorithm, called dynamic improved exemplar-based subspace clustering (DI-ESC), is proposed, which consists of two phases, i.e., initialization and online clustering. First, to achieve subspace clustering on subspace-imbalanced data, a static clustering approach called the improved ESC algorithm (I-ESC) is proposed. Second, based on the subspace clustering results obtained, DI-ESC can process the pulse stream in real-time and can further detect the emitter evolution by the proposed evolution detection strategy. The typically dynamic behavior of emitters such as appearing, disappearing and recurring can be detected and adapted by the DI-ESC. Extinct experiments on real-world emitter data show the sensitivity, effectiveness, and superiority of the proposed I-ESC and DI-ESC algorithms. - A Qualitative Case Study on Deconstructing Presence for Young Adults and Older Adults
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä(2022-12-01) Pouke, Matti; Ylipulli, Johanna; Uotila, Elmeri; Sitomaniemi, Anna-Kaisa; Pouke, Sakaria; Ojala, TimoIn this paper, we present the results of an exploratory qualitative case study on presence experienced by groups of young adults and older adults during their use of an interactive virtual reality application mixing realistic and fantasy elements. In contrast to most previous studies, we do not focus on a set of predetermined factors but instead adopt an open-ended qualitative approach to identify emerging factors from the users' experiences. We then analyze these factors against the place illusion/plausibility illusion (PI/PSI) framework of Skarbez, Neyret, et al. (2017) to investigate whether PI and PSI, as well as their contributing factors, can be separated. According to our findings, a user can experience PI and PSI independently from each other; however, they often appeared intermixed when investigated on the scope of the whole experience. Breaks in presence, as well as breaks in plausibility, could mostly, but not entirely, be attributed to immersion and coherence factors, respectively. An interesting finding is that both participant groups turned out to have two subgroups interpreting their experience with a particular frame of reference of differing expectations. These frames of reference affected not only PSI, as expected, but PI as well, suggesting that coherence could be a contributing factor to both PI and PSI. Our contribution adds to the relatively small body of research investigating the separation of PI and PSI. Our exploratory findings can be utilized as directions for designing future confirmatory studies. - Secure and efficient reactive video surveillance for patient monitoring
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä(2016-01-02) Braeken, An; Porambage, Pawani; Gurtov, Andrei; Ylianttila, MikaVideo surveillance is widely deployed for many kinds of monitoring applications in healthcare and assisted living systems. Security and privacy are two promising factors that align the quality and validity of video surveillance systems with the caliber of patient monitoring applications. In this paper, we propose a symmetric key-based security framework for the reactive video surveillance of patients based on the inputs coming from data measured by a wireless body area network attached to the human body. Only authenticated patients are able to activate the video cameras, whereas the patient and authorized people can consult the video data. User and location privacy are at each moment guaranteed for the patient. A tradeoff between security and quality of service is defined in order to ensure that the surveillance system gets activated even in emergency situations. In addition, the solution includes resistance against tampering with the device on the patient’s side. - Self-damping of the relaxation oscillations in miniature pulsed transmitter for sub-nanosecond-precision, long-distance LIDAR
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä(2020-12) Vainshtein, Sergey; Duan, Guoyong; Rahkonen, Timo; Taylor, Zachary; Zemlyakov, Valery; Egorkin, Vladimir; Smolyanskaya, Olga; Skotnicki, Thomas; Knap, WojciechPeak power is a critical factor for sub-nanosecond-pulsed transmitters utilizing laser diodes (LD) and applied to long distance LIDARs (light detection and ranging) for drones and automotive applications. Receiver speed is not anymore a limiting factor thanks to replacing linear (typically avalanche) detectors and a broad-band amplifier with a single photon avalanche detector (SPAD). Consequently the transmitters become the bottle neck in the resolution and ranging. The simplest and lowest-possible-cost transmitter consists of a switch, an LD, a storage capacitor C, and unavoidable parasitic loop inductance L. In the resulting resonant circuit, the principal problem consists of suppressing relaxation oscillations. Traditional way of oscillation damping reduce peak current and increase the pulse width. Here we show that specific transient properties of a Si avalanche switch solves the problem automatically provided the inductance is sufficiently low. This finding advances the state-of-the-art by reaching 90 W/1ns/200 kHz pulses from a miniature low-cost transmitter based on Si avalanching bipolar junction transistor (ABJT). Besides, the same self-damping effect may be realized in other switches maintaining significant residual voltage despite of fast current reduction. - Sequentially optimized projections in x-ray imaging
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä(2021-07) Burger, M.; Hauptmann, A.; Helin, T.; Hyvönen, N.; Puska, J. P.This work applies Bayesian experimental design to selecting optimal projection geometries in (discretized) parallel beam x-ray tomography assuming the prior and the additive noise are Gaussian. The introduced greedy exhaustive optimization algorithm proceeds sequentially, with the posterior distribution corresponding to the previous projections serving as the prior for determining the design parameters, i.e. the imaging angle and the lateral position of the source-receiver pair, for the next one. The algorithm allows redefining the region of interest after each projection as well as adapting parameters in the (original) prior to the measured data. Both A and D-optimality are considered, with emphasis on efficient evaluation of the corresponding objective functions. Two-dimensional numerical experiments demonstrate the functionality of the approach. - Study of butyl-amine nanocrystal cellulose in the flotation of complex sulphide ores
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä(2019-10-20) Lopéz, Raquel; Jordão, Helga; Hartmann, Robert; Ämmälä, Ari; Carvalho, M. TeresaFroth flotation is a widely used process for the beneficiation of complex sulphide ores. Thiol collectors (mostly xanthates) are usually effective collectors for sulphide minerals but may have a low selectivity between different sulphide minerals when associated in complex sulphide ores. Additionally, a concern is their suggested harmfulness on human health and impact on the environment. In this study, a green sustainable reagent, butyl-amine cellulose (BAC), was synthesized from hardwood kraft pulp, a renewable abundant resource, for the selective separation of chalcopyrite and sphalerite. The performance evaluation was made using samples of two ores containing chalcopyrite and sphalerite, one was from Panasqueira mine (Portugal) and the other with a different mineral association (from the massive sulphide deposits of the Iberian Pyrite Belt). The study demonstrated that when chalcopyrite is associated with sphalerite, BAC is selective for chalcopyrite, i.e., it is a collector for this mineral and not for sphalerite. The recovery of chalcopyrite in the floated product was a function of interaction between BAC concentration and pulp pH. The study showed that the novel cellulose-based collector had a better performance than the reagents used in the industrial flotation of Panasqueira ore. - Towards versatile access networks
A3 Kirjan tai muun kokoomateoksen osa(2023-06-06) Ghoraishi, Mir; Alexiou, Angeliki; Cogalan, Tezcan; Conrat, Jean Marc; De Guzman, Mar Francis; Devoti, Francesco; Eappen, Geoffrey; Fang, Chao; Frenger, Pål; Girycki, Adam; Guo, Hao; Halbauer, Hardy; Haliloglu, Omer; Haneda, Katsuyuki; Koffman, Israel; Kyösti, Pekka; Leinonen, Marko; Li, Yinggang; Madapatha, Charitha; Makki, Behrooz; Navarro-Ortiz, Jorge; Nguyen, Le Hang; Nimr, Ahmad; Pärssinen, Aarno; Pollin, Sofie; Pryor, Simon; Puerta, Rafael; Rahman, Md Arifur; Ramos-Munoz, Juan J.; Ranjbar, Vida; Roth, Kilian; Sarajlic, Muris; Sciancalepore, Vincenzo; Svensson, Tommy; Tervo, Nuutti; Wolfgang, AndreasCompared to its previous generations, the 5th generation (5G) cellular network features an additional type of densification, i.e., a large number of active antennas per access point (AP) can be deployed. This technique is known as massive multipleinput multiple-output (mMIMO) [1]. Meanwhile, multiple-input multiple-output (MIMO) evolution, e.g., in channel state information (CSI) enhancement, and also on the study of a larger number of orthogonal demodulation reference signal (DMRS) ports for MU-MIMO, was one of the Release 18 of 3rd generation partnership project (3GPP Rel-18) work item. This release (3GPP Rel-18) package approval, in the fourth quarter of 2021, marked the start of the 5G Advanced evolution in 3GPP. The other items in 3GPP Rel-18 are to study and add functionality in the areas of network energy savings, coverage, mobility support, multicast broadcast services, and positioning. - A Volumetric Pitzer Model for Aqueous Solutions of Zinc Sulfate up to Near-Saturation Concentrations at Temperatures from 293.15 to 393.15 K and Pressures up to 10 MPa
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä(2021-01-14) Vielma, Tuomas; Hnedkovsky, Lubomir; Uusi-Kyyny, Petri; Salminen, Justin; Alopaeus, Ville; Lassi, Ulla; Hefter, GlennLiterature data for the volumetric properties of aqueous solutions of zinc sulfate have been compiled and compared with extensive recently available measurements. A semi-empirical Pitzer model has been derived from these data that reproduces the apparent molar volumes and compressibilities of zinc sulfate solutions with good accuracy to near-saturation concentrations (m ≲ 3.0 mol·kg-1) over the temperature range 293.15 ≤ T/K ≤ 393.15 and at pressures up to 10 MPa, using standard volumes, V°, obtained by additivity of ionic values from the literature. By including the dependence of V° on the compressibility of pure water, the model was able to predict apparent molar volumes with good accuracy even up to 100 MPa at 298 K. Of potential use for engineering applications, imposition of the inequality (∂2Vφ/∂T2)p,m < 0 to the Pitzer model has created the possibility of physically reasonable extrapolations to temperatures well beyond the parameterization range.