CrowdPickUp:task pick-up in the wild

Abstract. This thesis investigates the feasibility and performance of different types of crowdsourcing tasks picked-up in the wild i.e., situated, location-based and general through the implementation and evaluation of the CrowdPickUp crowdsourcing platform. We describe in detail the implementation process of CrowdPickUp, which we then used in a study where workers could earn coins on the basis of task completion and use their earned coins to buy different available items of their own choice using CrowdPickUp’s web shop integrated within our system. During the study, we recorded the average completion time and accuracy of different crowdsourcing tasks. The key findings show that our platform was able to generate high quality contributions in a composite environment. Finally, we conclude the thesis by discussing the importance and usefulness of different crowdsourcing tasks designed for our crowdsourcing system and our possible future work within the area of crowdsourcing task-pickup system.Tiivistelmä. Tämä diplomityö tutkii joukkouttamisen suorituskykyä ja mahdollisuuksia erityyppisten tehtävien avulla. Tehtävät jaetaan työntekijöille luonnollisissa olosuhteissa paikkasidonnaisesti työssä kehitetyn CrowdPickUp-alustan avulla. Työ kuvailee yksityiskohtaisesti kehitetyn alustan sovelluskehitysprosessin. Tämän jälkeen valmista alustaa käytettiin käyttäjäkokeissa, joissa työntekijät pystyivät ansaitsemaan virtuaalivaluuttaa, jolla pystyi ostamaan erilaisia palkintoja. Kokeen aikana tutkimme ja tallensimme monenlaista tietoa, kuten esimerkiksi suoritetun työn tarkkuutta ja keskimääräistä tehokkuutta. Työn päälöydökset osoittavat, että alustamme kykeni tuottamaan korkealaatuista työtä luonnollisissa olosuhteissa ja ilman tutkijoiden jatkuvaa läsnäoloa. Lopuksi diplomityö keskustelee löydösten ja kehitystyön tärkeyttä sekä soveltuvuutta erilaisten tehtävien suorittamisalustaksi. Lisäksi esittelemme ideoita, joilla työtä voi kehittää eteenpäin entistä hyödyllisemmäksi tutkimusinstrumentiksi

The Potential of Precipitable Water Vapour Measurements from Global Navigation Satellite Systems in Luxembourg

The primary objectives of this research were to investigate the potential of precipitable water vapour (PWV) estimates derived from Global Navigation Satellite Systems (GNSS) measurements, firstly, for short-term weather forecasting based on numerical weather prediction (NWP) in Luxembourg and its surroundings and, secondly, for monitoring climate on regional and global scales. The suitability of real-time (RT) zenith total delay (ZTD) estimates obtained from three different precise point positioning (PPP) software packages was assessed by comparing them with the state-of-the-art product from the International GNSS Service (namely the IGS Final troposphere product) as well as collocated radiosonde (RS) observations. It was found that the RT-PPP ZTD estimates from two of the three software packages meet the threshold requirements for NWP nowcasting. The biases between the RT-PPP ZTD and the reference ZTD were found to be stable over time for all the RT-PPP ZTD solutions. A millimetre-level impact on the RT-PPP ZTD estimates was also observed when integer ambiguities were resolved. The impact of assimilating GNSS-derived near real-time (NRT) ZTD in the Applications of Research to Operations at Mesoscale (AROME) NWP model using a three-dimensional, variational (3D-VAR) assimilation scheme on the quality of weather forecasts for Luxembourg was studied. It was found that the assimilation of GNSS-derived ZTD systematically improves the atmospheric humidity short-range forecasts in comparison to other water vapour observing systems (radio soundings, satellite radiances, surface networks). Examination of several case studies revealed the ability of the ZTD observations to modify the intensity and location of predicted precipitation in accordance with previous studies. The addition of ZTD from the dense GNSS network in Wallonie (Belgium) was also found to be beneficial by improving the prediction of rainfall patterns in Luxembourg. The 2D maps of IWV obtained from the hourly NRT system were compared with cloud distribution and precipitation maps from satellite and weather radar data, respectively, and a good agreement in the location of the front system was found. A rise in IWV was recorded during a precipitation event in Luxembourg and it was shown that by observing the IWV change over the ground-based GNSS stations in Luxembourg in NRT, it is possible to determine the speed and direction of the passing fronts and hence storms can also be tracked. A 5-year long global reprocessed GNSS data set containing over 400 ground-based GNSS stations and based on the double differencing strategy has been used to validate the ZTD estimates obtained from the climate reanalysis model of the European Centre for Medium-range Weather Forecasts (ECMWF) namely the ECMWF ReAnalysis-Interim (ERA-Interim) in different climate zones. It was found that the correlation coefficient between the GNSS-derived ZTD observations and the ZTD modeled by ERA-Interim ranges from 0.87 to 1.00. Higher correlation coefficients were found for the stations belonging to the climate zones with lower amount of water vapour. Furthermore, it was found that the mean, SDev and RMS of the differences depends on periodicity in the residuals, altitude of the stations in a particular zone as well as the topographic variation in the zone. Monthly and seasonal means of GNSS-derived ZTD (ZTDgnss) were computed using a global ZTDgnss dataset consisting of 19-years of data and over 400 stations to study the climate variability in different climate zones. In terms of seasonal means, it was found that the climate zones in the northern hemisphere have ZTD maxima in Boreal Summer (June-July-August) whereas those in the southern hemisphere have ZTD maxima in Austral Summer (December-January-February). Monthly and seasonal variability in ZTDgnss was also studied for the locations of 6 ground-based GNSS (SPSLux) stations in Luxembourg. It was found that all the 6 SPSLux stations experience the same monthly and seasonal variability of ZTDgnss. In terms of monthly variation, it was found that the maxima in ZTDgnss occurs around the month of July for all the 6 SPSLux stations whereas in terms of seasonal variation, the location of maxima was found to be in Summer (June-July-August). The suitability of the ZTD derived using precise point positioning (PPP) strategy for climate monitoring applications was studied through its comparison with the ZTD estimates derived using double differenced positioning (DDP) using a global network of 114 stations and duration of 1 year. The mean differences between the two were found to be ranging from -3.35 to 2.37 mm over different climate zones. Furthermore, correlation coefficients ranging from 0.90 and 1.00 were found between the ZTD obtained using the two processing strategies. It was found that use of higher elevation cut-off angles and tropospheric mapping functions based on NWP improves the agreement between the PPP and DDP solutions

Discrete and Continuous Optimization Methods for Self-Organization in Small Cell Networks - Models and Algorithms

Self-organization is discussed in terms of distributed computational methods and algorithms for resource allocation in cellular networks. In order to develop algorithms for different self-organization problems pertinent to small cell networks (SCN), a number of concepts from discrete and continuous optimization theory are employed. Self-organized resource allocation problems such as physical cell identifier (PCI) assignment and primary component carrier selection are formulated as discrete optimization problems. Distributed graph coloring and constraint satisfaction algorithms are used to solve these problems. The PCI assignment is also discussed for multi-operator heterogeneous networks. Furthermore, different variants of simulated annealing are proposed for solving a graph coloring formulation of the orthogonal resource allocation problem. In the continuous optimization domain, a network utility maximization approach is considered for solving different resource allocation problems. Network synchronization is addressed using greedy and gradient search algorithms. Primal and dual decomposition are discussed for transmit power and scheduling weight optimizations, under a network-wide power constraint. Joint optimization over transmit powers and multi-user scheduling weights is considered in a multi-carrier SCN, for both maximum rate and proportional-fair rate utilities. This formulation is extended for multiple-input multiple-output (MIMO) SCNs, where apart from transmit powers and multi-user scheduling weights, the transmit precoders are also optimized, for a generic alpha-fair utility function. Optimization of network resources over multiple degrees of freedom is particularly effective in reducing mutual interference, leading to significant gains in network utility. Finally, an alternate formulation of transmit power allocation is considered, in which the network transmit power is minimized subject to the data rate constraints of users. Thus, network resource allocation algorithms inspired by optimization theory constitute an effective approach for self-organization in contemporary as well as future cellular networks

Evaluation of GNSS as a Tool for Monitoring Tropospheric Water Vapour

Global Navigation Satellite Systems have the potential to become a significant tool in climate research due to the fact that GNSS data can be processed in order to estimate the propagation delay experienced by the signal in atmosphere. If the ground pressure and temperature is known, the signal propagation path delay can be related to the amount of water vapour in the atmosphere. This thesis project focuses on the evaluation of GNSS as a tool for atmospheric water vapour estimation. In the first part of the project, various GNSS data processing software packages were compared by processing the same set of data and performing a statistical comparison of the estimates of zenith total delay obtained by each package. The software packages compared are GIPSY‐OASIS, Bernese GNSS Processing Software, GAMIT and magicGNSS. Also different strategies and methods, such as double‐differencing and precise point positioning,  are  investigated.  The  output from the  packages  is  validated  using  delay measurements obtained from ECMWF and RCA numerical models. It was observed that the output from climate models agrees with that from the software packages and the output from various software packages have a similarity between each other within 3 millimeters. In the second part of the project, simulations of new GNSS are carried out using in‐house software developed at Chalmers and SP Technical Research Institute of Sweden in order to investigate new methods and possible future improvements. The effect of local errors on atmospheric delay estimates from GPS, GLONASS and Galileo was studied through simulations. A hypothetical system formed by combination of the constellations of GPS, GLONASS and Galileo was also simulated and it was found to be least susceptible to local errors. Simulations were performed by varying some Keplerian orbital elements for Galileo system and it was observed that an orbit inclination between 60 degree and 65 degree would have been optimum for Galileo system

Is it T3 thyrotoxicosis? A case of falsely elevated tri-iodothyronine (T3) levels leading to a diagnosis of multiple myeloma

We are presenting a case of falsely elevated T3 levels in a patient due to interference from monoclonal immunoglobulins. A 56-year-old, clinically euthyroid man referred to the endocrinology clinic of the Aga Khan university, Karachi Pakistan, for possible T3 thyrotoxicosis after thyroid function tests revealed total T3 \u3e12.32 nmol/L (reference range 0.6-2.79), normal TSH, and total T4 level. There was a mismatch in clinical and laboratory parameters and preliminary laboratory results were suggestive of thyroid binding globulin abnormalities. Further evaluation in this context unmasked multiple myeloma. The presence of monoclonal immunoglobulins can lead to assay interference and spurious results. To the best of our knowledge, this is the second case defining the cause of falsely elevated T3 levels, due to assay interferences with binding of T3 only to monoclonal immunoglobulins

Impact of International Trade and Trade Duties on Current Account Balance of the Balance of Payment: A study of N-11 Countries

This study is aimed to investigate the impact of international trade and trade duties upon the current account balance of the balance of payment of N-11 countries. Two constituents of each factor have been considered for the purpose of analysis. For International trade, import (IMPT) and export (EXPT) of goods and services have been considered whereas, for trade duties, taxes on international trade (TOIT) and customs and other import duties (CID) have been taken as the research variables whereas, current account balance (CAB) has been taken as the dependent variable. For the purpose of analysis panel data of N-11 countries for 27 years from 1990 to 2016 has been tested using different econometric technique such as Panel unit root test, Panel co-integration test, Hausman test, Panel regression analysis and Panel causality analysis. The results demonstrate that overall research variables are co-integrated and having long term relationship and affecting each other in the conventional manner. Notably, it is observed via results that in case of N-11 countries the CAB itself is the regulating factor and all other factors are adjusted according to the movement of CAB. The study provides recommendations for the rectification of current account deficit position and also provides scope for future research as well

Relationship between estimated average glucose (eAG) and fasting plasma glucose in a cohort of Pakistani diabetic subjects

Introduction: Scientific literature is scarce on the utility of estimated average glucose (eAG) from Pakistan. Hence, there is a dire need to evaluate the relationship between eAG and fasting plasma glucose (FPG), in order to enhance our understanding of eAG and its usefulness. This study aims to investigate the relationship between FPG and eAG in diabetic patients calculated using HbA1C.Materials and methods: A retrospective study was conducted at the Aga Khan University, Karachi, Pakistan. The medical records of both genders in the age range of 18-60 years, presenting as outpatients at the endocrine clinic, labeled as DM, were reviewed from January 2013 to December 2019. The subjects were divided into three groups A (\u3c130 mg/Dl), B (130-179 mg/Dl), and C (\u3e180 mg/Dl) based on FPG levels. A correlation was compared using Spearman’s correlation. Box, whisker plots, and scatter plots were computed by R studio.Results: After excluding those with missing values for either serum Cr, FPG, and HbA1c and sub-optimal renal function based on estimated glomerular filtration rate (eGFR) a total of 4,673 cases were analyzed. Subgroup A showed good glycemic control, whereas subgroup C showed poor glycemic control. The difference between eAG and FPG was significant (p \u3c 0.0001). eAG values were found to be elevated than FPG values in groups A and B and almost the same in group C, whereas a moderately significant correlation with eAG and FPG in all three groups.Conclusion: The correlation between eAG and FPG varies with blood glucose control and was significantly higher in the poorly controlled diabetes group. As the association between the FPG and eAG levels varies with the extent of blood glucose control, reporting eAG with HbA1c by a simple formula, at no additional cost will prove to be beneficial for clinical care