Search

A classical result of K. L. Chung and W. Feller deals with the partial sums S k S_k arising in a fair coin-tossing game. If N n N_n is the number of “positive” terms among S 1 S_1 , S 2 S_2 , …, S n S_n then the quantity P ( N 2 n = 2 r ) P(N_{2n} = 2r) takes an elegant form. We lift the restriction on an even number of tosses and give a simple expression for P ( N 2 n + 1 = r ) P(N_{2n+1} = r) , r = 0 r = 0 , 1 1 , 2 2 , …, 2 n + 1 2n+1 . We get to this ansatz by adaptating the Feynman–Kac methodology.

Paper waste in the mockups design with regular, irregular, and amorphous patterns is a critical problem in digital printing presses. Paper waste reduction directly impacts production costs, generating business and environmental benefits. This problem can be mapped to the two-dimensional irregular bin-packing problem. In this paper, an iterated local search algorithm using a novel neighborhood structure to detect overlaps between amorphous shapes is introduced. This algorithm is used to solve the paper waste problem, modeled as one 2D irregular bin-packing problem. The experimental results show that this approach works efficiently and effectively to detect and correct the overlaps between regular, irregular, and amorphous figures.

Applying professional-vision skills to classroom situations depends on knowledge about what matters in these situations. In an experiment with 85 biology pre-service teachers, we investigated a 90-min intervention combining both acquisition and application of knowledge about tutoring. The interven-tion started with an introductory text, followed by classroom video examples. Students who read a text on concrete tutoring strategies made more references to pedagogical concepts in their analyses than students who read about generic video observational guidelines. We conclude that combining a short, focused theoretical introduction and video analysis is a promising method to broadly anchor professional-vision training within teacher education.(c) 2023 Elsevier Ltd. All rights reserved.

The aim of this study was to assess postures and movements of the trunk and upper arm during paper mill work, and to determine the extent to which they differ depending on method of assessment. For each of 28 paper mill workers, postures and movements were assessed during three full shifts using inclinometer registration and observation from video. Summary metrics for each shift, e.g., 10th, 50th, and 90th posture percentile, were averaged across shifts and across workers. In addition, the standard deviation between workers, and the standard deviation between shifts within worker were computed. The results showed that trunk and arm postures during paper mill work were similar to other occupations involving manual materials handling, but the velocities of arm movements were lower. While postures determined by inclinometry and observation were similar on a group level, substantial differences were found between results obtained by the two methods for individual workers, particularly for extreme postures. Thus, measurements by either method on individuals or small groups should be interpreted with caution.

Wood-processing industries must be able to estimate the properties of wood to properly manage the wood production chain. For this estimation, changes in certain characteristics over time must be identified so that they can be used to rapidly differentiate a clone or species. Of interest are acoustical, geometrical, physical, and mechanical properties, all measurable in seedlings. Thus, the objective of this research was to analyze the evolution of the ultrasonic wave propagation velocity, diameter, height, basic density, strength, and stiffness starting in nursery seedlings at 3 months of age to trees at 6 years of age, which is the cutting age used by the pulp and paper industry in Brazil. The experiment was conducted in 121 seedlings and 270 trees of three Eucalyptus clones. Within the age range analyzed, the results indicated that all parameters have the potential to be used in a predictive model to estimate the future quality of clones, although the predictive value of these parameters varies. The ultrasonic wave propagation velocity was the only property that maintained the coherent differences among clones from the seedling to the cutting age (6 yr old). The strength, stiffness, diameter, and height maintained coherence from 12 months to the cutting age, whereas the basic density was maintained from the age of 24 months to the cutting age. We hope that these results will contribute to improving the methods to select clones.

The need to account for potential losses in rare events is of utmost importance for corporations operating in the financial sector. Common measurements for potential losses are Value at Risk and Expected Shortfall. These are measures of which the computation typically requires immense Monte Carlo simulations. Another measurement is the Advanced Internal Ratings-Based model that estimates the capital requirement but solely accounts for a single risk factor. As an alternative to the commonly used time-consuming credit risk methods and measurements, Michael Pykhtin presents methods to approximate the Value at Risk and Expected Shortfall in his paper Multi-factor adjustment from 2004. The thesis’ main focus is an elucidation and investigation of the approximation methods that Pykhtin presents. Pykhtin’s approximations are thereafter implemented along with the Monte Carlo methods that is used as a benchmark. A recreation of the results Pykhtin presents is completed with satisfactory, strongly matching results, which is a confident verification that the methods have been implemented in correspondence with the article. The methods are also applied on a small and large synthetic Nordea data set to test the methods on alternative data. Due to the size complexity of the large data set, it cannot be computed in its original form. Thus, a clustering algorithm is used to eliminate this limitation while still keeping characteristics of the original data set. Executing the methods on the synthetic Nordea data sets, the Value at Risk and Expected Shortfall results have a larger discrepancy between approximated and Monte Carlo simulated results. The noted differences are probably due to increased borrower exposures, and portfolio structures not being compatible with Pykhtin’s approximation. The purpose of clustering the small data set is to test the effect on the accuracy and understand the clustering algorithm’s impact before implementing it on the large data set. Clustering the small data set caused deviant results compared to the original small data set, which is expected. The clustered large data set’s approximation results had a lower discrepancy to the benchmark Monte Carlo simulated results in comparison to the small data. The increased portfolio size creates a granularity decreasing the outcome’s variance for both the MC methods, and the approximation methods, hence the low discrepancy. Overall, Pykhtin’s approximations’ accuracy and execution time are relatively good for the experiments. It is however very challenging for the approximate methods to handle large portfolios, considering the issues that the portfolio run into at just a couple of thousand borrowers. Lastly, a comparison between the Advanced Internal Ratings-Based model, and modified Value at Risks and Expected Shortfalls are made. Calculating the capital requirement for the Advanced Internal Ratings-Based model, the absence of complex concentration risk consideration is clearly illustrated by the significantly lower results compared to either of the other methods. In addition, an increasing difference can be identified between the capital requirements obtained from Pykhtin’s approximation and the Monte Carlo method. This emphasizes the importance of utilizing complex methods to fully grasp the inherent portfolio risks. Behovet av att ta hänsyn till potentiella förluster av sällsynta händelser är av yttersta vikt för företag verksamma inom den finansiella sektorn. Vanliga mått på potentiella förluster är Value at Risk och Expected Shortfall. Dessa är mått där beräkningen vanligtvis kräver enorma Monte Carlo-simuleringar. Ett annat mått är Advanced Internal Ratings-Based-modellen som uppskattar ett kapitalkrav, men som enbart tar hänsyn till en riskfaktor. Som ett alternativ till dessa ofta förekommande och tidskrävande kreditriskmetoderna och mätningarna, presenterar Michael Pykhtin metoder för att approximera Value at Risk och Expected Shortfall i sin uppsats Multi-factor adjustment från 2004. Avhandlingens huvudfokus är en undersökning av de approximativa metoder som Pykhtin presenterar. Pykhtins approximationer implementeras och jämförs mot Monte Carlo-metoder, vars resultat används som referensvärden. Ett återskapande av resultaten Pykhtin presenterar i sin artikel har gjorts med tillfredsställande starkt matchande resultat, vilket är en säker verifiering av att metoderna har implementerats i samstämmighet med artikeln. Metoderna tillämpas även på ett litet och ett stor syntetiskt dataset erhållet av Nordea för att testa metoderna på alternativa data. På grund av komplexiteten hos det stora datasetet kan det inte beräknas i sin ursprungliga form. Således används en klustringsalgoritm för att eliminera denna begränsning samtidigt som egenskaperna hos den ursprungliga datamängden fortfarande bibehålls. Vid appliceringen av metoderna på de syntetiska Nordea-dataseten, identifierades en större diskrepans hos Value at Risk och Expected Shortfall-resultaten mellan de approximerade och Monte Carlo-simulerade resultaten. De noterade skillnaderna beror sannolikt på ökade exponeringar hos låntagarna och att portföljstrukturerna inte är förenliga med Pykhtins approximation. Syftet med klustringen av den lilla datasetet är att testa effekten av noggrannheten och förstå klustringsalgoritmens inverkan innan den implementeras på det stora datasetet. Att gruppera det lilla datasetet orsakade avvikande resultat jämfört med det ursprungliga lilla datasetet, vilket är förväntat. De modifierade stora datasetets approximativa resultat hade en lägre avvikelse mot de Monte Carlo simulerade benchmark resultaten i jämförelse med det lilla datasetet. Den ökade portföljstorleken skapar en finkornighet som minskar resultatets varians för både MC-metoderna och approximationerna, därav den låga diskrepansen. Sammantaget är Pykhtins approximationers noggrannhet och utförandetid relativt bra för experimenten. Det är dock väldigt utmanande för de approximativa metoderna att hantera stora portföljer, baserat på de problem som portföljen möter redan vid ett par tusen låntagare. Slutligen görs en jämförelse mellan Advanced Internal Ratings-Based-modellen, och modifierade Value at Risks och Expected shortfalls. När man beräknar kapitalkravet för Advanced Internal Ratings-Based-modellen, illustreras saknaden av komplexa koncentrationsrisköverväganden tydligt av de betydligt lägre resultaten jämfört med någon av de andra metoderna. Dessutom kan en ökad skillnad identifieras mellan kapitalkraven som erhålls från Pykhtins approximation och Monte Carlo-metoden. Detta understryker vikten av att använda komplexa metoder för att fullt ut förstå de inneboende portföljriskerna.

We show that there is a little mistake in an implication in a paper of Bob Gilmer on rngs.

Although replaced by the internet-based TOEFL (iBT), the paper-based TOEFL (PBT) was still used in some countries until July 2017. This natural experiment investigates a case where, November 2006–May 2009, a testing center in the Middle East did not follow TOEFL time interval protocol at that time, with 1,575 test takers allowed to attempt paper TOEFL versions as frequently as desired. This study analyzes score increase/decrease with frequency of/time intervals between attempts at taking paper TOEFL version(s). These test takers attempted the TOEFL multiple times, with 48% taking it at least twice, some up to 22 times. Results indicate a negative relationship between number of attempts and score increases/decreases between consecutive tests greater than Standard Error of Measurement (>SEM), and a positive relationship between score change and average time interval. Score decreases showed greater variability, with smaller average time interval than increases. Percentages of individuals’ score decrease averaged in repeater group positively correlated with number of attempts. Consecutive test scores decreased (>SEM) at least once for 900 test takers. Score decreases showed greater variability and significantly smaller average time intervals than increases. There was very strong positive correlation between increase in number of attempts and consecutive score decreases. Repetitions within one week showed greater score variations. These findings raise questions about construct-irrelevant effects of test repetition and time interval on score change. One explanation is that score increases >SEM occurred gradually over more time, in smaller amounts, in keeping with increases in ability through learning, but decreases >SEM occurred in shorter time intervals and larger amounts, possibly reflecting more immediate negative affect-related factors.

The paper presents the study results of paper trapping during inkjet printing which contains cellulose pulp from the inner bark layer of mulberry branches. The connection between the print density and the paper surface structure, in particular, water absorption and raggedness, is established. The study of the stepwise gradation transition and color rendition, the graphic accuracy of reproduction of the slur element of the image is carried out. Densitometric and microscopic analysis of the impressions printed on an inkjet printer was performed. It was revealed that the pigments of water ink, depending on the microgeometry of the paper surface, penetrated deeper in different ways. It was found that the maximum thickness of the paint layer, expressed using the optical density values for the primary colors of the subtractive synthesis, and the best color reproduction were provided by the surface of the paper sample with 100 % addition of cellulose pulp from the inner layer of the bark of mulberry tree branches, which has the least roughness, according to the scanning probe microscope Solver HV. Recommendations are given for testing paper data on inkjet printers that use pigment inks and are less demanding on the surface properties of paper, or by printing methods that do not use low-viscosity printing inks.

In museum lighting, Chinese paper cultural relics are prone to cracking, embrittlement and other photochemical damage after absorbing the spectral energy of light sources. Owing to the different absorption and reflection characteristics of paper for different bands, optimizing the spectrum compositions of light sources can provide effective protection, the basis of which is to clarify the influence rule of spectra on the paper. However, the methods of color difference and Raman spectroscopy, which are widely used in the current research, cannot scientifically measure the lighting damage. In this study, Fourier transform infrared spectroscopy was used as the evaluation method, and 10 kinds of narrow-band lights were used as the experimental light source to conduct a 1440 h irradiation experiment on the samples of the ancient Chinese Xuan paper. The oxidation index was calculated as the evaluation index based on the infrared spectra measured every 240 hours, and a mathematical model for the response rate of paper to spectrum and exposure was established. 610 spectra were obtained with the 10 kinds of narrow-band lights combined and superimposed. The color rendering indexes of the above spectra were calculated, and 9,477 spectra that meet the requirements of viewing indicators were obtained. By calculating the damage degree of the above spectra with the model, the optimal LED spectrum with the minimum damage which met the visual requirements was obtained. Then it was input into the 10-channel spectral simulation system for spectral restoration. Two kinds of lights commonly used in lighting for paper cultural relics were selected to conduct a comparative experiment. The results showed that the optimal LED spectrum reduced damage degree by 49.4% and 59.7% respectively compared with the two kinds of contrast light sources, and was beneficial to energy saving.

In many manufacturing industries, the production process involves the production of objects and the cutting of such objects into smaller pieces in order to meet a specific demand. In the optimization of these processes, one can identify the lot sizing and the cutting stock problems. In the literature, these problems are mostly separately dealt. However, treating these two problems in an integrated approach can decrease overall costs. In this research, we deal with the coupled lot sizing and cutting stock problem. It is proposed a mathematical formulation for the production and cutting of paper based on a real case, which considers setup costs and limited machine capacity in the production process of the objects. For the solution of the proposed model, we used a column generation approach and a relax-and-fix heuristic. Computational tests were carried out in order to analyze the methodology used in the resolution of the model. The results showed to be competitive in a reasonable computational time.

In this study, a simple and fast procedure was developed and validated for the determination of bisphenol A (BPA) in paper products using synchronous fluorescence spectroscopy. The method was used for the determination of BPA in thirteen types of paper products, including thermal receipt papers, lottery tickets, bus tickets, business cards, mailing envelopes, flyers, napkins, printing paper, food contact paper, kitchen rolls, toilet paper, newspapers, and magazines. BPA was found in 98% of thermal receipt papers (n = 341) at concentrations ranging from below the limit of quantification (LOQ) to 27.7 mg g−1 with a geometric mean of 14.6 mg g−1 and a median of 17.7 mg g−1. The detection rate for other paper products was 96%, with BPA concentrations ranging from below the LOQ to 379 µg g−1 and a median of 17.3 µg g−1. The estimated daily intake for the adjusted bodyweight of BPA (calculated at median concentrations) through dermal absorption from handling papers was 14.5 and 1070 ng day−1 for the general population and occupationally-exposed individuals, respectively. The proposed analytical method is simple, fast, and cost-effective for the determination of BPA in paper samples. Moreover, an estimated daily exposure of Brazilians to BPA through dermal absorption from handling different types of papers is shown.

Paper is a material that are produced by pulp that are being compressed, which are one of the leading cause of pollution in an aquatic environment. The aim of the study was to produce a non-chemical treatment natural paper from pomelo albedo waste. The Citrus Maxima (Pomelo) albedo wastes were heated in distilled water and converted into pulp. The pulp was placed in a handmade frame and oven-dried at 60°C for an hour. A paper quality survey was conducted among diploma in pharmacy students (N=36) using a structured interviewing questionnaire. Eighty percent of the respondents agree/strongly agree that different colour of pen, 2B pencil, colour pencil, and crayon can be used as in written or sketch on the albedo pomelo paper. There is no clear tendency to result on the usage of highlighter and correction Tape. Most of the respondents disagree with smoothness, elasticity, and waterproof of the paper. The Pomelo paper is potential as an alternative eco-friendly natural paper for writing and colouring with different materials. The pomelo paper making process can be shared as an educational kit, especially to children, to expose them on the papermaking process.

Aim of study: It was aimed to rank financial performance of companies in the paper industrytraded at BIST.Material and methods: The financial performances of sevencompanies in the paper industry which are tradedon the Borsa İstanbul (BIST) were determinedby using financial data in 2016. For this purpose, ten financial ratios were obtainedfrom the financial data of companies, each of which had its own superiority. The datawere conducted by the TOPSIS (Technique for Order Preference by Similarity toIdeal Solution) method which is the "Multi Criteria Decision Making"(MCDM) method to interpret.Main results: The results indicated that the companies were rankedfollows; ALKA, KARTN, VKING, BAKAB, TIRE, OLMIP and KAPLM based on thefinancial performance scores.Research highlights: In Turkey, production in paper industry meets nearly half of the consumption and paper demand are met by imports.The high prices of energy and initial investment costs encourage imports ofpaper products and they prevent newinvestments. From this perspective, growth, development and high performance ofpaper companies will keep this industry alive., BİST’deişlem gören kağıt sektöründeki firmaların TOPSIS yöntemiyle finansalperformanslarının değerlendirilmesiÖzetÇalışmanın amacı: BİST’de işlem gören kağıtsektöründeki firmaların finansal performanslarına göre sıralanmasıamaçlanmıştır.Materyal ve yöntem: Borsa İstanbul’da (BIST) işlemgören kağıt sektöründeki 7 firmanın 2016 yılına ait verileri kullanılarakfinansal performansları belirlenmeye çalışılmıştır. Bu amaçla, şirketlere aitfinansal verilerden 10 finansal oran elde edilmiştir ve bu finansal oranlarınher biri diğerlerine göre üstünlüğe sahiptir. Bütünleşik bir değerlendirmeyapılması amacıyla, veriler “Çok Kriterli Karar Verme” (ÇKKV) yöntemlerindenolan TOPSIS (Technique for Order Preference by Similarity to Ideal Solution)yöntemi ile değerlendirilmiştir.Sonuçlar: Şirketler finansal performanslarına göreALKA, KARTN, VKING, BAKAB, TIRE, OLMIP ve KAPLM olarak sıralanmıştır..Araştırma vurguları: Ülkemiz kağıt sektöründegerçekleştirilen üretim ile tüketimin yarısı karşılanabilmekte ve kağıtihtiyacı ithalatla karşılanmaktadır. Enerji fiyatlarının ve ilk yatırımmaliyetlerinin yüksek olması yeni yatırımları engellerken ithalata teşviketmektedir. Bu bakımdan sektörde var olan firmaların gelişmesi, büyümesi veperformanslarının yüksek olması sektörü canlı tutacaktır.

Biological examinations given to 16-18 year olds were analyzed over an eight year period for the number and type of mathematical questions. There was an increase in the number of questions which included skills in graphing, rate, percentage, and statistics. Difficulties with graphs, calculations and indices are discussed. (AJ)