Ensemble of radial basis neural networks with k-means clustering for heating energy consumption prediction

U radu je predložen i prikazan ansambl neuronskih mreža za predviđanje potrošnje toplote univerzitetskog kampusa. Za obučavanje i testiranje modela korišćeni su eksperimentalni podaci. Razmatrano je poboljšanje tačnosti predviđanja primenom k-means metode klasterizacije za generisanje obučavajućih podskupova neuronskih mreža zasnovanih na radijalnim bazisnim funkcijama. Korišćen je različit broj klastera, od 2-5. Izlazi članova ansambla su kombinovani primenom aritmetičkog, težinskog i osrednjavanja metodom medijane. Pokazano je da ansambli neuronskih mreža ostvaruju bolje rezultate predviđanja nego svaka pojedinačna mreža članica ansambla. PR Data used for this paper were gathered during study visit to NTNU, as a part of the collaborative project: Sustainable energy and environment in Western Balkans.For the prediction of heating energy consumption of university campus, neural network ensemble is proposed. Actual measured data are used for training and testing the models. Improvement of the prediction accuracy using k-means clustering for creating subsets used to train individual radial basis function neural networks is examined. Number of clusters is varying from 2 to 5. The outputs of ensemble members are aggregated using simple, weighted and median based averaging. It is shown that ensembles achieve better prediction results than the individual network

Various multistage ensembles for prediction of heating energy consumption

Feedforward neural network models are created for prediction of daily heating energy consumption of a NTNU university campus Gloshaugen using actual measured data for training and testing. Improvement of prediction accuracy is proposed by using neural network ensemble. Previously trained feed-forward neural networks are first separated into clusters, using k-means algorithm, and then the best network of each cluster is chosen as member of an ensemble. Two conventional averaging methods for obtaining ensemble output are applied; simple and weighted. In order to achieve better prediction results, multistage ensemble is investigated. As second level, adaptive neuro-fuzzy inference system with various clustering and membership functions are used to aggregate the selected ensemble members. Feedforward neural network in second stage is also analyzed. It is shown that using ensemble of neural networks can predict heating energy consumption with better accuracy than the best trained single neural network, while the best results are achieved with multistage ensemble

Multistage ensemble of feedforward neural networks for prediction of heating energy consumption

Feedforward neural network models are created for prediction of heating energy consumption of a university campus. Actual measured data are used for training and testing the models. Multistage neural network ensemble is proposed for the possible improvement of prediction accuracy. Previously trained feed-forward neural networks are first separated into clusters, using k-means algorithm, and then the best network of each cluster is chosen as a member of the ensemble. Three different averaging methods (simple, weighted, and median) for obtaining ensemble output are applied. Besides this conventional approach, single radial basis neural network in the second level is used to aggregate the selected ensemble members. It is shown that heating energy consumption can be predicted with better accuracy by using ensemble of neural networks than using the best trained single neural network, while the best results are achieved with multistage ensemble

Molecular-genetic mechanisms of resistance in the prognosis of patients with multiple myeloma

Multipli mijelom (MM) je bolest za koju se vezuje visok stepen genomske nestabilnosti. Karakteriše se numeričkim i strukturnim hromozomskim aberacijama, koje zauzimaju centralno mesto u prognoznom profilu bolesnika sa MM. Cilj: Utvrditi uticaj postojanja molekularno-genetičkih aberacija: del1p, +1q21, translokacije t(4;14), t(14;16) i del 17p na terapijski odgovor i preživljavanje bolesnika sa multiplim mijelomom. Utvrditi uticaj ekspresije cereblona (CRBN), MDR (multidrug resitance protein) i LRP (lung resistance protein) na terapijski odgovor i preživljavanje bolesnika sa multiplim mijelomom. Metod: Ispitivana su 92 novootkrivena bolesnika sa multiplim mijelomom, koji su dijagnostikovani i lečeni u Klinici za hematologiju KCS u periodu od decembra 2011. do januara 2014. godine. Molekularno-genetička ispitivanja koja su predmet ovog istraživanja su sprovedena u Laboratoriji za citogenetiku i molekularnu genetiku Klinike za hematologiju Kliničkog centra Srbije i u Institutu za molekularnu genetiku i genetičko inženjerstvo (IMGG) u Beogradu. Prisustvo viskorizičkih citogenetskih abnormalnosti utvrđivano je metodom interfazne in situ hibridizacije (iFISH), a nivo ekspresije CRBN, MDR i LRP kod naših ispitanika utvrđivan je metodom „real-time“ PCR. Rezultati: Metodom iFISH prisustvo visokorizičnih citogenetskih abnormalnosti: t (4;14), t(14;16), del 17p utvđeno je kod 14 (15,2%) bolesnika. Kod 27 (29,3%) bolesnika utvrđeno je prisustvo abnormalnosti hromozoma 1. Kod 8 (8,7%) bolesnika delecija 1p, a kod 19 (20,6%) dodatne kopije hromozoma 1q. Kod 4 (4,34%) bolesnika bila je prisutna hiperdiploidija +1q. Bolesnici sa abnormalnostima hromozoma 1 su se karakterisali kraćim trajanjem remisije na granici statističke značajnosti i jasno kraćim preživljavanjem u odnosu na bolesnike bez ovih abnormalnosti. Medijana ekspresije CRBN kod bolesnika sa MM je bila značajno viša u odnosu na zdravu kontrolu. Korelacija izmedju visoke ekspresije CRBN i povoljnog terapijskog odgovora bila je prisutna u grupi bolesnika koji su lečeni talidomidom, što je u skladu sa podacima iz literature, te visoka ekspresija CRBN može da posluži kao surogat marker za bolest niskog rizika. Analiza nivoa ekspresije RQ_MDR1 pokazala je da je njena vrednost bila niža kod bolesnka koji su reagovali na lečenje 252.1±46.2 u odnosu na one koji su umrli 493.8±168, ali T testom nije postignuta statistička značajnost (p=0,233). Slični rezultati su dobijeni i kod RQ_LRP 181.9±31.5 prema 242.5±33.8, takođe bez postizanja statističke značajnosti (p=0,213)...Multiple myeloma (MM) is a disease that is associated with a high degree of genomic instability. It is characterized by numerical and structural chromosomal aberrations, which occupy a central place in the prognosis profile of patients with MM. Aim: To determine the influence of the existence of molecular-genetic aberrations: del1p, + 1q21, translocation t (4; 14), t (14; 16) and del 17p on the therapeutic response and survival of patients with multiple myeloma. Determine the effect of cereblone expression (CRBN), MDR (multidrug resistance protein) and LRP (lung resistance protein) on the therapeutic response and survival of patients with multiple myeloma. Method: 92 newly discovered patients with multiple myeloma, who were diagnosed and treated in the Clinic of Hematology of the Clinical Centre of Serbia in the period from December 2011 to January 2014, were examined. Molecular-genetic studies that are the subject of this research were conducted at the Laboratory for Cytogenetics and Molecular Genetics of the Clinic of Hematology of the Clinical Center of Serbia and the Institute for Molecular Genetics and Genetic Engineering (IMGG) in Belgrade. The presence of high-risk cytogenetic abnormalities was determined by interphase in situ hybridization (iFISH), and the level of expression of CRBN, MDR and LRP in our subjects was determined by the method of "real-time" PCR. Results: The iFISH method of presence of high-risk cytogenetic abnormalities: t (4; 14), t (14; 16), del 17p was found in 14 (15.2%) patients. In 27 (29.3%) patients, the presence of abnormalities of chromosome 1 was determined. In 8 (8.7%) patients deletion 1p, and in 19 (20.6%) additional copies of chromosomes 1q. In 4 (4.34%) patients, hyperdiploidy + 1q was present. Patients with abnormalities of chromosome 1 were characterized by shorter duration of remission at the boundary of statistical significance and clearly shorter survival compared to patients without these abnormalities. Median expression of CRBN in patients with MM was significantly higher in relation to healthy control. Correlation between high expression of CRBN and favorable therapeutic response was present in the group of patients treated with thalidomide, which is in accordance with literature data, and high expression of CRBN can serve as a surrogate marker for low-risk disease. Analysis of the expression level RQ_MDR1 showed that its value was lower in patients who responded to treatment 252.1 ± 46.2 compared to those who died 493.8 ± 168, but did not achieve statistical significance with the T test (p = 0.233). Similar results were obtained in RQ_LRP 181.9 ± 31.5 versus 242.5 ± 33.8, also without statistical significance (p = 0.213)..

Trigeneration and advantage analysis in compare to conventional air-conditioning of data center

For a data centre in Belgrade, a comparison was made regarding initial investment and operation costs between a trigeneration system (combined heat and power production) and a conventional air‑conditioning system. According to the current ratio of natural gas prices and electricity prices, trigeneration is not profitable for consumers in Serbia. However, according to the ratio of energy prices in European countries, economic feasibility of trigeneration as well as its high energy efficiency is the reason to expect a major market break of trigeneration systems.Za jedan računski centar u Beogradu izvršeno je poređenje investicionih i eksploatacionih troškova za konvencionalni sistem klimatizacije takvih objekata i postrojenja za trigeneraciju (kombinovana proizvodnja električne energije i toplote za grejanje i hlađenje). Prema trenutnom odnosu cena osnovnih energenata u ovim sistemima (električne energije i prirodnog gasa), sistemi trigeneracije nisu isplativi korisnicima u Srbiji. Međutim, prema cenama energenata u okruženju, trigeneracija je ne samo energetski, nego i ekonomski isplativa i očekuje se njen veći prodor na tržište

Trigeneration and advantage analysis in compare to conventional air-conditioning of data center

For a data centre in Belgrade, a comparison was made regarding initial investment and operation costs between a trigeneration system (combined heat and power production) and a conventional air‑conditioning system. According to the current ratio of natural gas prices and electricity prices, trigeneration is not profitable for consumers in Serbia. However, according to the ratio of energy prices in European countries, economic feasibility of trigeneration as well as its high energy efficiency is the reason to expect a major market break of trigeneration systems.Za jedan računski centar u Beogradu izvršeno je poređenje investicionih i eksploatacionih troškova za konvencionalni sistem klimatizacije takvih objekata i postrojenja za trigeneraciju (kombinovana proizvodnja električne energije i toplote za grejanje i hlađenje). Prema trenutnom odnosu cena osnovnih energenata u ovim sistemima (električne energije i prirodnog gasa), sistemi trigeneracije nisu isplativi korisnicima u Srbiji. Međutim, prema cenama energenata u okruženju, trigeneracija je ne samo energetski, nego i ekonomski isplativa i očekuje se njen veći prodor na tržište

Konkurentnost odabranih zemalja jugoistočne Europe na tržištu drvenih podova Europske unije

Selected South-Eastern European countries (SEEC - Albania, Bosnia and Herzegovina, Croatia, Montenegro, North Macedonia, Serbia and Slovenia) represent significant producers and exporters of wood flooring in Europe. In 2018, 9.4 % of Europe’s wood flooring production originated from this region. The region is a net exporter of wood flooring since it exports over 50 % of total production. The most important market for the export of wood flooring is the European Union with a share of over 60 % in total exports. Trends in this market are important for manufacturers and exporters from the region. Therefore, the analysis of the impact of the European Union imports on wood flooring production in the SEEC was conducted by application of econometric modelling. The parameters of the obtained model show that the increase of approximately 0.75 % could be expected in the production of wood flooring in selected South-Eastern European countries for each precentral increase in the European Union imports. In addition to these results, the paper presents the analysis of the competitiveness of wood flooring export from the region measured by the Competitiveness Growth Index (RCA1). The aim of this analysis was to quantify the level of their price and non-price competitiveness in the European Union market. Conducted analyses show that the Competitiveness Growth Index (RCA1) had positive values (higher than one) for most significant countries from the SEEC for most of the observed period.Odabrane zemlje jugoistočne Europe (SEEC – Albanija, Bosna i Hercegovina, Hrvatska, Crna Gora, Sjeverna Makedonija, Srbija i Slovenija) značajni su proizvođači i izvoznici drvenih podova u Europi. U 2018. godini 9,4 % europske ponude drvenih podova proizvedeno je upravo u toj regiji. Regija je neto izvoznik drvenih podova jer izvozi više od 50 % ukupne proizvodnje. Najvažnije je tržište za izvoz drvenih podova Europska unija, na koju otpada više od 60 % ukupnog izvoza. Trendovi na tržištu Europske unije vrlo su važni za proizvođače i izvoznike iz promatranih zemalja SEEC-a. Stoga je primjenom ekonometrijskog modeliranja analiziran utjecaj uvoza Europske unije na proizvodnju drvenih podova u SEEC regiji. Parametri dobivenog modela pokazuju da se sa svakim postotkom povećanja uvoza u Europsku uniju može očekivati rast proizvodnje drvenih podova u odabranim zemljama jugoistočne Europe za oko 0,75 %. Osim rezultata provedene analize, u radu su izneseni i rezultati analize konkurentnosti izvoza drvenih podova iz zemalja SEEC-a mjereni indeksom rasta konkurentnosti (RCA1). Cilj analize bio je kvantificiranje razine njihove cjenovne i necjenovne konkurentnosti na tržištu Europske unije. Provedene analize pokazuju da je indeks rasta konkurentnosti (RCA1) za najznačajnije zemlje SEEC-a u većini godina promatranog razdoblja imao pozitivne vrijednosti (veće od 1)

Some significant remarks on multivalued Perov type contractions on cone metric spaces with a directed graph

Using the approach of so-called c-sequences introduced by the fifth author in his recent work, we give much simpler and shorter proofs of multivalued Perov's type results with respect to the ones presented in the recently published paper by M. Abbas et al. Our proofs improve, complement, unify and enrich the ones from the recent papers. Further, in the last section of this paper, we correct and generalize the well-known Perov's fixed point result. We show that this result is in fact equivalent to Banach's contraction principle

Some significant remarks on multivalued Perov type contractions on cone metric spaces with a directed graph

Using the approach of so-called c-sequences introduced by the fifth author in his recent work, we give much simpler and shorter proofs of multivalued Perov's type results with respect to the ones presented in the recently published paper by M. Abbas et al. Our proofs improve, complement, unify and enrich the ones from the recent papers. Further, in the last section of this paper, we correct and generalize the well-known Perov's fixed point result. We show that this result is in fact equivalent to Banach's contraction principle

Analiza i predviđanje potrošnje energije poslovne zgrade korišćenjem višestruko linearno regresionog modela, metode potpornih vektora i neuronske mreže

Considering the constant growth of interest in energy efficiency in the building sector, it is necessary to apply and improve existing and also to develop new methods for prediction and analysis of building energy consumption. In this paper cooling consumption of the model of a typical commercial building in Belgrade is analyzed. Detailed energy simulation is done using software HAP (Hourly Analysis Program). The influence of various building characteristics is investigated, and for creating building consumption database, three variables that most largely affect the cooling consumption are chosen: specific lighting power, window area and window shade coefficient. Those three parameters are varied and 245 simulations in total are used for creating and testing the prediction models. The multiple linear model is created and the obtained equation is used for cooling consumption evaluation taking these three building parameters as input. The artificial neural network and support vector machine (SVM) models are also developed for prediction and their results are compared with linear regression model. It has been shown that the statistical methods, such are neural networks and support vector machines can achieve much higher accuracy in prediction than the linear regression model, gaining almost perfect match with simulated values (mean absolute percentage error for testing the SVM model 0,26%).S obzirom na stalni porast interesovanja za povećanje energetske efikasnosti u zgradarstvu, neophodno je primenjivati i unapređivati postojeće i razvijati nove metode za predviđanje i analizu potrošnje zgrada. Na modelu tipične poslovne zgrade u Beogradu ispitivan je uticaj različitih karakteristika zgrade. Simulacija potrošnje energije na časovnoj bazi urađena je korišćenjem programa HAP (Hourly Analysis Program). Za dalju analizu izabrana su tri faktora koja u najvećoj meri utiču na potrošnju energije za hlađenje: specifična instalisana snaga osvetljenja, udeo prozora u spoljašnjem zidu i koeficijent propustljivosti Sunčevog zračenja kroz prozore. Analiza je vršena za različite vrednosti ova tri parametra. Za kreiranje i testiranje višeparametarskog modela korišćeno je 245 simulacija. Predložen je višestruko linearni model koji može da se koristi za određivanje potrošnje energije za hlađenje, a koji kao ulazne veličine koristi pomenuta tri parametra. U cilju predviđanja potrošnje, razvijeni su modeli primenom metode potpornih vektora (support vector machine) i veštačkih neuronskih mreža i izvršeno je poređenje rezultata sa višestruko linearnim modelom. Pokazano je da modeli zasnovani na metodi potpornih vektora i neuronskim mrežama postižu veću tačnost predvidjanja u odnosu na linearni višeparametarski model