Aplikasi Model Proportional Hazard Cox pada Waktu Tunggu Kerja Lulusan Jurusan Matematika Fakultas MIPA Universitas Sriwijaya

Penelitian ini bertujuan untuk (1) menentukan nilai peluang dari waktu mendapatkan pekerjaan per-tama lulusan, (2) mengetahui bagaimana pengaruh beberapa karateristik terhadap waktu mendapatkan pe-kerjaan pertama lulusan dengan menerapkan model proportional hazard Cox. Subjek penelitian terdiri atas 35 orang lulusan Jurusan Matematika, Fakultas Matematika dan Ilmu Pengetahuan Alam, Universitas Sriwijaya yang lulus pada tahun 2012. Karakteristik-karakteristik yang diamati adalah usia, masa studi, IPK, skor TOEFL, pendidikan orang tua, pengalaman organisasi, dan pengalaman kerja. Hasil dari penelitian ini memperlihakan bahwa peluang tertinggi bagi para lulusan untuk mendapatkan pekerjaan pertama adalah mulai awal bulan ketiga sampai akhir bulan keempat setelah wisuda, yaitu sebesar 0,31579. Karakteristik yang berpengaruh sig-nifikan terhadap waktu mendapatkan pekerjaan pertama adalah pengalaman organisasi. Model terbaik yang terbentuk adalah ℎ , = ℎ0 exp(−0,979 6) dengan nilai rasio hazard sebesar 0,376. Hal ini berarti bahwa lulusan yang memiliki pengalaman organisasi memiliki peluang 0,376 kali lebih besar untuk mendapatkan pe-kerjaan pertama setelah wisuda

Towards the Design of a Synchronous Virtual Learning System

The field of education has undoubtedly been affected by the penetrating influence of information and communication technology, characterized by improved access to the internet, and the increasing use of computing devices. However, education in Africa generally and specifically in Nigeria and other developing countries still face a 21st Century challenge in making education available and accessible to all. To this end therefore, this paper presents a conceptual approach, as to how tailor made e-learning services could be realized and integrated with a real time video conference server and any existing learning management system in order to facilitate a synchronous virtual learning environment in making education accessible and available to both remote students (distance learning students) and onsite users in Universities and other related educational institutes. It proposes a functional framework to exemplify educational services such as file sharing to enhance collaboration, a digital resource center for retrieval of both free and paid relevant academic resource. A conference room for real time classroom participation which learning platform should provide in order to enhance both teaching and learning performance of course instructors and their students respectively is also proposed. It provides an operational design which describes how custom made e-learning portal integrated with an Open source Video Conference server could be realized, in facilitating a synchronous virtual learning service. Furthermore, it proposes a Virtual Learning Network architecture to show how both remote and onsite students could optimize quality network access in realizing these electronic learning services

Calibrating the Standard Path Loss Model for Urban Environments using Field Measurements and Geospatial Data

Path loss model is essential to achieving a successful cellular network planning and deployment. Despite the benefits derived from models that have become standard and are widely adopted, the actual applicability of these models depends on the local ambient characteristics of the environment. This means that environments that substantially differ from those used to create the models will not be adequately characterized, and so the resulting cellular planning fails to some extent. Therefore, the models used may substantially benefit from calibration to ensure fitness with the actual measurements collected over a given area. This paper presents a calibration procedure based on the Standard Propagation Model (SPM), and applies to the 900 MHz and 1800 MHz bands. In particular, signal strength data were collected along four routes in residential areas, and the results were then processed using the ATOLL network planning tool. Overall, we find that, after a proper calibration, the SPM provides a much better fitness, achieving average Mean Absolute Error (MAE), Root Mean Square Error (RMSE) and Standard Deviation (SDE) values of 5.40 dB, 6.90 dB and 4.29 dB, respectively, which are significantly better than the reference values without calibration (18.32 dB, 21.55 dB and 11.34 dB, respectively)

Data on the key performance indicators for quality of service of GSM networks in Nigeria

In thisdataarticle,theKeyPerformanceIndicators(KPIs)for Quality ofService(QoS)ofGlobalSystemforMobileCommu- nications (GSM)networksinNigeriaareprovidedandanalyzed. The dataprovidedinthispapercontaintheCallSetupSuccessRate (CSSR), DropCallRate(DCR),Stand-aloneDedicatedChannel (SDCCH) congestion,andTraffic Channel(TCH)congestionforthe four GSMnetworkoperatorsinNigeria(Airtel,Etisalat,Glo,and MTN). ThesecomprehensivedatawereobtainedfromtheNigerian Communications Commission(NCC).Significant differencesin each oftheKPIsforthefourquartersofeachyearwerepresented based onAnalysisofVariance(ANOVA).ThevaluesoftheKPIs wereplottedagainstthemonthsoftheyearforbettervisualization and understandingofdatatrendsacrossthefourquarters.Multiple comparisons ofthemean-quarterlydifferencesoftheKPIswere also presentedusingTukey'sPostHoctest.Publicavailabilityand further interpretationanddiscussionoftheseusefulinformation will assistthenetworkproviders,Nigeriangovernment,localand international regulatorybodies,policymakers,andotherstake- holders inensuringaccessofpeople,machines,andthingstohigh qualitytelecommunicationsservice

Spatial Variability Study of Duty Cycle in GSM 900 and 1800 MHz Bands in Rural and Urban Environments

This paper examines the spatial variability of duty cycle in the GSM 900 and 1800 MHz bands within Kwara State, Nigeria. The results show spatial variance in the duty cycle with average occupancies of 1.67%, 17.76%, 10.55% and 0.39%, 11.00% and 5.11 in the rural, urban and all locations for 900 and 1800 MHz bands. Findings also show that there is very high positive correlation between rural 900/1800 MHz and urban 900/1800 MHz. But very high negative correlations exits between urban 900 and rural 1800, and urban 1800 and rural 1800. There is a weak and negative correlation between rural and urban 900 MHz, rural-urban 1800. These results clearly showthe abundance of unutilised spectrum within the GSM bands. Therefore, regulatory commissions should adopt flexible spectrum reuse strategy to relax the regulatory bottlenecks to maximize the scarce radio resources in the licensed bands, especially for rural network deployment

Compact automatic modulation recognition using over-the-air signals and FOS features

The recent deployment of automatic modulation recognition (AMR) for cognitive radio (CR) systems has significantly enhanced spectrum sensing capabilities. The utilization of real-time over-the-air digital radio frequency (RF) data for the development of a digital spectrum sensing model based on the automatic modulation classification (AMC) is presented in this study as a step for incorporating opportunistic spectrum sensing onto the NomadicBTS architecture. Some digital modulation techniques were studied for second- generation (2G) through fourth-generation (4G) technology. The raw RF signal dataset was digitized and curated, while non-complex first-order statistical (FOS) features were used with algorithms based on the Scaled conjugate gradient (SCG) and Levenberg-Marquardt (LM) to find the best learning algorithm for the generated AMR model. The results show that the developed AMR model has a very high likelihood of correctly classifying signals, with distinct patterns for each of the features of FOS. The results are compared to reveal a least mean square error (MSE) of 0.0131 with a maximum accuracy of 93.5 percent when the model was trained with seventy (70) neurons in the hidden layer using the LM method. The best model's accuracy will allow for the most precise identification of spectrum holes in the bands under consideratio

Path Loss Predictions in the VHF and UHF Bands Within Urban Environments: Experimental Investigation of Empirical, Heuristics and Geospatial Models

(c) 2019 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other users, including reprinting/ republishing this material for advertising or promotional purposes, creating new collective works for resale or redistribution to servers or lists, or reuse of any copyrighted components of this work in other works.[EN] Deep knowledge of how radio waves behave in a practical wireless channel is required for effective planning and deployment of radio access networks in urban environments. Empirical propagation models are popular for their simplicity, but they are prone to introduce high prediction errors. Different heuristic methods and geospatial approaches have been developed to further reduce path loss prediction error. However, the efficacy of these new techniques in built-up areas should be experimentally verified. In this paper, the efficiencies of empirical, heuristic, and geospatial methods for signal fading predictions in the very high frequency (VHF) and ultra-high frequency (UHF) bands in typical urban environments are evaluated and analyzed. Electromagnetic field strength measurements are performed at different test locations within four selected cities in Nigeria. The data collected are used to develop path loss models based on artificial neural network (ANN), adaptive neuro-fuzzy inference system (ANFIS), and Kriging techniques. The prediction results of the developed models are compared with those of selected empirical models and field measured data. Apart from Egli and ECC-33, the root mean squared error (RMSE) produced by all other models under investigation are considered acceptable. Specifically, the ANN and ANFIS models yielded the lowest prediction errors. However, the empirical models have the lowest standard deviation errors across all the bands. The findings of this study will help radio network engineers to achieve efficient radio coverage estimation; determine the optimal base station location; make a proper frequency allocation; select the most suitable antenna; and perform interference feasibility studies.This work was supported jointly by the funding received from IoT-Enabled Smart and Connected Communities (SmartCU) Research Cluster and the Center for Research, Innovation and Discovery (CUCRID) of Covenant University, Ota, Nigeria.Faruk, N.; Popoola, SI.; Surajudeen-Bakinde, NT.; Oloyede, AA.; Abdulkarim, A.; Olawoyin, LA.; Ali, M.... (2019). Path Loss Predictions in the VHF and UHF Bands Within Urban Environments: Experimental Investigation of Empirical, Heuristics and Geospatial Models. IEEE Access. 7:77293-77307. https://doi.org/10.1109/ACCESS.2019.2921411S7729377307

Large-scale radio propagation path loss measurements and predictions in the VHF and UHF bands

For decades now, a lot of radio wave path loss propagation models have been developed for predictions across different environmental terrains. Amongst these models, empirical models are practically the most popular due to their ease of application. However, their prediction accuracies are not as high as required. Therefore, extensive path loss measurement data are needed to develop novel measurement-oriented path loss models with suitable correction factors for varied frequency, capturing both local terrain and clutter information, this have been found to be relatively expensive. In this paper, a large-scale radio propagation path loss measurement campaign was conducted across the VHF and UHF frequencies. A multi-transmitter propagation set-up was employed to measure the strengths of radio signals from seven broadcasting transmitters (operating at 89.30, 103.5, 203.25, 479.25, 615.25, 559.25 and 695.25 MHz respectively) at various locations covering a distance of 145.5 km within Nigerian urban environments. The measurement procedure deployed ensured that the data obtained strictly reflect the shadowing effects on radio signal propagation by filtering out the small-scale fading components. The paper also, examines the feasibilities of applying Kriging method to predict distanced-based path losses in the VHF and UHF bands. This method was introduced to minimize the cost of measurements, analysis and predictions of path losses in built-up propagation environment

Antimicrobial resistance among migrants in Europe: a systematic review and meta-analysis

BACKGROUND: Rates of antimicrobial resistance (AMR) are rising globally and there is concern that increased migration is contributing to the burden of antibiotic resistance in Europe. However, the effect of migration on the burden of AMR in Europe has not yet been comprehensively examined. Therefore, we did a systematic review and meta-analysis to identify and synthesise data for AMR carriage or infection in migrants to Europe to examine differences in patterns of AMR across migrant groups and in different settings. METHODS: For this systematic review and meta-analysis, we searched MEDLINE, Embase, PubMed, and Scopus with no language restrictions from Jan 1, 2000, to Jan 18, 2017, for primary data from observational studies reporting antibacterial resistance in common bacterial pathogens among migrants to 21 European Union-15 and European Economic Area countries. To be eligible for inclusion, studies had to report data on carriage or infection with laboratory-confirmed antibiotic-resistant organisms in migrant populations. We extracted data from eligible studies and assessed quality using piloted, standardised forms. We did not examine drug resistance in tuberculosis and excluded articles solely reporting on this parameter. We also excluded articles in which migrant status was determined by ethnicity, country of birth of participants' parents, or was not defined, and articles in which data were not disaggregated by migrant status. Outcomes were carriage of or infection with antibiotic-resistant organisms. We used random-effects models to calculate the pooled prevalence of each outcome. The study protocol is registered with PROSPERO, number CRD42016043681. FINDINGS: We identified 2274 articles, of which 23 observational studies reporting on antibiotic resistance in 2319 migrants were included. The pooled prevalence of any AMR carriage or AMR infection in migrants was 25·4% (95% CI 19·1-31·8; I2 =98%), including meticillin-resistant Staphylococcus aureus (7·8%, 4·8-10·7; I2 =92%) and antibiotic-resistant Gram-negative bacteria (27·2%, 17·6-36·8; I2 =94%). The pooled prevalence of any AMR carriage or infection was higher in refugees and asylum seekers (33·0%, 18·3-47·6; I2 =98%) than in other migrant groups (6·6%, 1·8-11·3; I2 =92%). The pooled prevalence of antibiotic-resistant organisms was slightly higher in high-migrant community settings (33·1%, 11·1-55·1; I2 =96%) than in migrants in hospitals (24·3%, 16·1-32·6; I2 =98%). We did not find evidence of high rates of transmission of AMR from migrant to host populations. INTERPRETATION: Migrants are exposed to conditions favouring the emergence of drug resistance during transit and in host countries in Europe. Increased antibiotic resistance among refugees and asylum seekers and in high-migrant community settings (such as refugee camps and detention facilities) highlights the need for improved living conditions, access to health care, and initiatives to facilitate detection of and appropriate high-quality treatment for antibiotic-resistant infections during transit and in host countries. Protocols for the prevention and control of infection and for antibiotic surveillance need to be integrated in all aspects of health care, which should be accessible for all migrant groups, and should target determinants of AMR before, during, and after migration. FUNDING: UK National Institute for Health Research Imperial Biomedical Research Centre, Imperial College Healthcare Charity, the Wellcome Trust, and UK National Institute for Health Research Health Protection Research Unit in Healthcare-associated Infections and Antimictobial Resistance at Imperial College London