Background: The prevalence of loyalty programs used to attract and keep customers loyal to the company by making return purchases has increased in the marketing strategy used by more and more companies. It is in the nature of a wide variety of loyalty programs to offer consumers benefits in the future causing a liability for the offering business. According to IFRS 15 loyalty programs should be evaluated and presented in the company's financial statements to their fair value of financial commitment to its customers. Purpose: This study's purpose is to describe how and to what extent Swedish companies, that is required to use IFRS 15 in their accounting, reports on their loyalty programs in the annual report. In addition, the purpose is also to analyze and understand why Swedish companies report as they do and to analyze how the new accounting standard IFRS 15 has affected companies ́ yearly reports. Method: With detailed analysis of 14 company’s annual reports; 2 owned by the Swedishgovernment, 10 public trade companies and 2 former traded companies, and further detailed interviews with 4 out of these companies this study has obtained a wide understanding of how loyalty programs are disclosed in financial reports in a Swedish context. This study uses a qualitative method. Theoretical framework: This study bases its theoretical reference from the stakeholder theory, financial disclosure theory and Swedish regulations, this study explores IFRS 15 and loyalty programmes and the disclosure requirement in this accounting standard. Findings: The international accounting standard IFRS 15 clashes to some extent with Swedish accounting principles, which means that Swedish limited companies, for various reasons, choose not to provide more information about the loyalty program than they do. Among other things, companies have listened to auditors' guidelines on what needs to be reported, with reference to Swedish accounting principles, and also to some extent created their own practice when they choose to report equally to their competitors. From the majority of surveyed companies' financial reports, it is not possible for stakeholders to deduce how valuation took place, nor what risks the loyalty program may entail. The study has shown that the more extensive and complex loyalty program the company uses, the more assessments and assumptions in valuation that can be difficult to get accurate. By presenting a valuation model, companies could reduce the information gap between company management and the company's stakeholders, thus also reducing risks.The debt linked to the loyalty program can amount to large sums in relation to the company's results. At the same time, more and more companies are choosing to use loyalty programs and those companies that are already using loyalty programs expect them to grow. This means that the reporting of loyalty programs and the information companies choose to provide about these is becoming increasingly important. / Bakgrund: Utbredningen av lojalitetsprogram i företags affärsplan blir ett vanligare och av vanligare inslag i marknadsstrategier. Lojalitetsprogram används för att bygga relationer till kunder, skapa lojalitet och merförsäljning. Det ligger i många lojalitetsprogram natur att företaget utlovar framtida förpliktelser till sina kunder. I redovisningen uppstår således en skuld. Med anledning av att IFRS 15 blev efterträdaren till tidigare redovisningsstandard IFRIC 13 ska värdering av denna lojalitetsskuld värderas efter IFRS 15 femstegsmodell och särskilda upplysningar ska lämnas, företagen har en så kallad upplysningsplikt. Syfte: Syftet är dels att beskriva hur och i vilken omfattning svenska aktiebolag, som ska redovisa i enlighet med IFRS 15, redovisar sina lojalitetsprogram i årsredovisningen. Utöver det är syftet även att analysera och förstå varför svenska aktiebolag redovisar som de gör samt analysera om i kraft trädandet av den nya redovisningsstandarden IFRS 15 påverkat företagens redovisning. Metod: Med detaljerad analys av 14 företags årsredovisningar; 2 som ägs av den svenska staten, 10 börsnoterade och 2 tidigare börsnoterade och ytterligare detaljerade intervjuer med fyra av dessa företag har denna studie fått en bred förståelse för hur lojalitetsprogram redovisas i finansiella rapporter ur ett svenskt perspektiv. Därmed utgår studien från en kvalitativ metod. Teoretisk referensram: Denna studie baserar sin teoretiska referens från intressentteorin, teori om finansiell information och svenska redovisningslagar och den här studien undersöker lojalitetsprogram och upplysningsplikten efter IFRS 15 som redovisningsstandard. Slutsats: Den internationella redovisningsstandarden IFRS 15 krockar till viss del med svenska redovisningsprinciper vilket gör att svenska aktiebolag, av olika anledningar, väljer att inte lämna mer information kring lojalitetsprogrammet än vad de gör. Företag har bland annat visat sig lyssna på revisorers riktlinjer kring vad som behöver redovisas, med hänvisning till svenska redovisningsprinciper, och även till viss del skapat en egen praxis då de väljer att redovisa jämlikt sina konkurrenter. Ur majoriteten av undersökta företags finansiella rapporter är det inte möjligt för intressenter att utläsa hur värdering gått till och inte heller vilka risker lojalitetsprogrammet kan innebära. Det har i studien visat sig att ju mer omfattande och komplext lojalitetsprogram företaget använder sig av, desto fler bedömningar och antaganden vid värdering som kan vara svåra att få precisa. Genom att redovisa en värderingsmodell skulle företagen kunna minskainformationsgapet mellan företagsledningen och företagets intressenter, på så sätt även minska riskerna. Skulden kopplat till lojalitetsprogrammet kan utgöra stora summor i förhållande till företagets resultat. Samtidigt är det allt fler företag som väljer att använda sig av lojalitetsprogram och de företag som redan använder sig av lojalitetsprogram, förväntar sig att de ska växa. Detta medför att redovisningen av lojalitetsprogram och de upplysningar företagen väljer att lämna kring dessa blir av allt större betydelse.

The purpose of this study was to examine the effect of immersion in sodium hypochlorite on nickel titanium rotary files and determine whether resistance to fracture was influenced by the immersion time. 70 ISO size 25 0.04 taper nickel titanium K3 and Profile rotary instruments were immersed in 5.25% sodium hypochlorite for 1, 5, 15, 30, 60, and 120 minutes (n=5 each). Resistance to fracture was tested by rotating files at a 30 degree angle at 350 rpm in a universal testing machine. Time to fracture was recorded and analyzed by a two-way ANOVA. Within both file types, there was a decreased time to fracture with increased immersion time in sodium hypochlorite. K3 files required an average of 327 rotations to fracture, while Profiles required 420 rotations to fracture. Profiles required significantly more rotations to failure than K3 files.

K3 ENDO, PRO TAPER, AND PRO FILE SYSTEMS: BREAKAGE AND DISTORTION IN SEVERELY CURVED ROOTS OF MOLARS.By Matthew T. Ankrum, D.D.S.A Thesis submitted in partial fulfillment of the requirements for the degree of Master of Science at Virginia Commonwealth University.Virginia Commonwealth University, 2003Major Director: Gary R. Hartwell, D.D.S., M.S.Chairman and Professor, Department of EndodonticsIt was the aim of this study to investigate the incidence of file breakage and distortion when the Pro Taper, K3 Endo and ProFile systems were used to instrument canals in the severely curved roots of extracted molars.Forty-five roots of extracted mandibular and maxillary molars with curvatures between 40 and 75 degrees were chosen for use in this study. The roots in Group One were instrumented with the Pro File (PF) system and served as the control group. Roots in Group Two were instrumented with the Pro Taper (PT) system and those in Group Three were instrumented with the K3 Endo (K3) system. The three systems were used according to the manufacturers' instructions.The proportion of files distorted was 15.3% for the PF group, 2.4% for the PT group, and 8.3% for the K3 group. There was a statistically significant difference between the PF and PT groups (p = .0079). The percentage of broken files was 1.7% for the PF group, 6.0% for the PT group and 2.1% for the K3 group. No statistically significant differences were found between these three groups (p = .4243). The results of this study showed that these three rotary tapered systems were not significantly different with regard to breakage. There were significantly more distorted files in the PF group when compared to the PT group, with regard to distortion there was no significant difference between the PT and K3 and the PF and K3 groups.

Mobile Ad-Hoc Network (MANET) facilitates the creation of dynamic reconfigurable networks, without centralized infrastructure. MANET routing protocols have to face high challenges like link instability, node mobility, frequently changing topologies and energy consumption of node, due to these challenges routing becomes one of the core issues in MANETs. This Thesis mainly focuses on the reactive routing protocol such as Ad-Hoc On-Demand Distance Vector (AODV) routing protocol. Reliable and Efficient Reactive Routing Protocol (RERRP) for MANET has been proposed to reduce the link breakages between the moving nodes. This scheme selects a reliable route using Reliability Factor (RF); the RF considers Route Expiration Time and Hop Count to select a routing path with high reliability and have less number of hops. The simulation result shows that RERRP outperforms AODV and enhance the packet delivery fraction (PDF) by around 6% and reduces the network routing load (NRL) by around 30%. Broadcasting in MANET could cause serious redundancy, contention, and collision of the packets. A scheme, Effective Broadcast Control Routing Protocol (EBCRP) has been proposed for the controlling of broadcast storm problem in a MANET. The EBCRP is mainly selects the reliable node while controlling the redundant re-broadcast of the route request packet. The proposed algorithm EBCRP is an on-demand routing protocol, therefore AODV route discovery mechanism was selected as the base of this scheme. The analysis of the performance of EBCRP has revealed that the EBCRP have controlled the routing overhead significantly, reduces it around 70% and enhance the packet delivery by 13% as compared to AODV. An Energy Sensible and Route Stability Based Routing Protocol (ESRSBR) have also been proposed that mainly focuses on increasing the network lifetime with better packet delivery. The ESRSBR supports those nodes to participate in the data transfer that have more residual energy related to their neighbour nodes. The proposed protocol also keeps track of the stability of the links between the nodes. Finally, the ESRSBR selects those routes which consist of nodes that have more residual energy and have stable links. The comparative analysis of ESRSBR with AODV and recently proposed routing protocol called Link Stability and Energy Aware (LSEA) routing protocol revealed that the proposed protocol ESRSBR has a significantly affect the network lifetime, increases it around 10% and 13% as compared to LSEA and AODV protocols respectively. The ESRSBR also decreases the routing overhead by 22% over LSEA and by 38% over AODV.

A geometallurgical model is the combination of a spatial model representing an ore deposit and a process model representing the comminution and concentration steps in beneficiation. The process model itself usually consists of several unit models. Each of these unit models operates at a given level of detail in material characterization - from bulk chemical elements, elements by size, bulk minerals and minerals by size to the liberation level that introduces particles as the basic entity for simulation (Paper 1). In current state-of-the-art process simulation, few unit models are defined at the particle level because these models are complex to design at a more fundamental level of detail, liberation data is hard to measure accurately and large computational power is required to process the many particles in a flow sheet. Computational cost is a consequence of the intrinsic complexity of the unit models. Mineral liberation data depends on the quality of the sampling and the polishing, the settings and stability of the instrument and the processing of the data. This study introduces new tools to simulate a population of mineral particles based on intrinsic characteristics of the feed ore. Features are extracted at the meso-textural level (drill cores) (Paper 2), put in relation to their micro-textures before breakage and after breakage (Paper 3). The result is a population of mineral particles stored in a file format compatible to import into process simulation software. The results show that the approach is relevant and can be generalized towards new characterization methods. The theory of image representation, analysis and ore texture simulation is briefly introduced and linked to 1-point, 2-point, and multiple-point methods from spatial statistics. A breakage mechanism is presented as a cellular automaton. Experimental data and examples are taken from a copper-gold deposit with a chalcopyrite flotation circuit, an iron ore deposit with a magnetic separation process. This study is covering a part of a larger research program, PREP (Primary resource efficiency by enhanced prediction). / PREP

Etapas de cominuição representam uma grande parcela do capital e custo operacional em uma usina de processamento mineral. Em 1983, Cohen estimou que os processos de cominuição podem ser responsáveis por 30% a 50% do consumo energético da usina representando tipicamente 50% dos custos operacionais de uma mineração. Sendo assim, sua otimização está diretamente relacionada com a redução destes custos de operação. Entre os equipamentos de britagem, o moinho de martelos é aquele dedicado às operações que visam a alta taxa de redução com geração controlada de finos. Este britador é recomendado para minérios friáveis e pouco abrasivos, apresentando alta capacidade produtiva. O presente trabalho tem por objetivo propor e validar um modelo matemático para modelagem e simulação de moinho de martelos, visando a simulação do circuito da britagem industrial de beneficiamento de minério de ouro do Córrego do Sítio I, localizada em Santa Bárbara - MG. As simulações visaram identificar gargalos operacionais e estabelecer cenários que permitam otimizar o circuito estudado. A amostragem foi executada conforme o plano traçado. As amostras obtidas foram utilizadas tanto para a caracterização do minério quanto para a calibração do modelo do Caso Base da operação da usina. As simulações indicaram acréscimos significativos de vazão de alimentação na usina, a partir do aumento da velocidade de rotação do moinho de martelos, com uma tendência de geração maior de finos no processo. Para simulação do aumento de velocidade de rotação dos martelos foi criado um modelo com base na energia de quebra das partículas, associada aos incrementos correspondentes na energia cinética dos martelos. A fim de validar o modelo proposto, foram planejados ensaios específicos em moinho de martelos de laboratório, e executados com o mesmo minério alimentado na usina industrial selecionada. Os ensaios consistiram em variações de velocidade de rotação dos martelos, de forma a corresponder às simulações anteriormente realizadas do equipamento industrial. O modelo criado foi validado com base em campanha experimental específica. / Comminution represents a large portion of the capital and operating cost of a mineral processing plant. In 1983, Cohen estimated that comminution processes could account for 30% to 50% of the power consumption of the mill, and typically represents 50% of the operating costs of a mine. Therefore, its optimization is directly related to reduction of these operating costs. Among the crushing equipment, the hammer mill is one which is dedicated to operations that aim for high reduction ratio with controlled generation of fines. This crusher is recommended for friable and low abrasive ores presenting a high productive capacity. This study aims to develop a stepwise approach that allows the use of the classical crusher model (Whiten-Andersen) in modeling and simulation of circuits containing a hammer mill, simulating the resulting product according to variation of rotation speed within the equipment. The existing model for crushers developed by Whiten-Andersen considers the Perfect Mixing Model, which represents crushing through equations related to selection and breakage functions, that provide an equilibrium condition. The present work aims at the validation of a mathematical model of hammer mill, aiming at a simulation of the circuit of the industrial crushing of gold ore of Córrego do Sítio I, located in Santa Bárbara - MG. The simulations aimed at identifying operational bottlenecks and establishing scenarios that allow optimizing the studied circuit. Sampling was performed according to the drawn plan. The samples obtained were used both for the characterization of the ore and for the calibration of the Base Case model of the plant operation. The simulations indicated significant increases in feed flow at the plant, due to the increase in the speed of rotation of the hammer mill, with a trend of higher generation of fines in the process. To simulate the increase of rotational velocity of the hammers, a model was created based on the energy of breaking of the particles, associated to the corresponding increments in the kinetic energy of the hammers. In order to validate the proposed model, specific tests were planned in laboratory hammer mill, and executed with the same ore fed in the selected industrial plant. The tests consisted of variations in the speed of rotation of the hammers, in order to correspond to the previous simulations of the industrial equipment. The model created was validated based on specific experimental campaign.

Algoritmos computacionais e análise matemática têm sido grandes aliados na determinação de informação quantitativa extraída de observações experimentais. No presente trabalho, estudou-se a aplicação da metodologia do problema inverso em balanço populacional que descreve como varia a distribuição de tamanhos de moléculas poliméricas durante diferentes processos de degradação de polímeros. A evolução da distribuição durante o processo de quebra pode ser descrita matematicamente por equação de balanço populacional. No assim chamado problema inverso, as distribuições medidas experimentalmente são usadas para estimar os parâmetros do balanço populacional que descrevem, por exemplo, como as taxas de quebra variam ao longo do comprimento da cadeia e como variam com o tamanho da cadeia. Este problema inverso é conhecido por seu intrínseco mal condicionamento numérico. Um algoritmo previamente desenvolvido na literatura para problemas de quebra de gotas em emulsões líquidas, baseado no conceito de auto-similaridade das distribuições, foi adaptado e aplicado no presente trabalho para o problema de quebra de cadeias poliméricas durante a degradação do polímero. Dados experimentais de diferentes processos de degradação, obtidos da literatura, foram testados: degradação de polipropileno por radicais livres gerados por peróxidos, degradação de dextrana por hidrólise ácida, degradação ultra-sônica de dextrana, degradação mecânica por cisalhamento de poliestireno, degradação enzimática de guar, e degradação ultrassônica de guar. As distribuições de taxa de quebra obtidas para os diferentes sistemas foram analisadas e interpretadas em termos das particularidades e do mecanismo de cada tipo de processo de degradação, visando um melhor entendimento fundamental dos processos. / Computational algorithms are used to obtain quantitative information from experimental observations. The aim of the present work was the application of the methodology of inverse problem in population balance used to describe the evolution of the chain length distribution in different polymer degradation processes. The time evolution of the chain length distribution during the polymer breakage can be mathematically described by a population balance equation. In the so-called inverse problem, experimentally measured distributions are used to estimate the parameters of the population balance, such as the distribution of breakage rate along the chain and as function of the chain length. The inverse problem is known to be an ill-conditioned numerical problem. An algorithm previously developed in the literature for liquid droplet breakage in liquid emulsions, based on the concept of self-similarity of the distributions, was adapted and applied in the present work for the problem of polymer scission during polymer degradation. Experimental data of degradation of different polymers were taken from the literature and used to test the procedure: free-radical degradation of polypropylene acid hydrolysis of dextran, ultrasonic degradation of dextran, shear-induced mechanical degradation of polystyrene, enzymatic hydrolysis of guar; and ultrasonic degradation of guar. The breakage rate distribution obtained for the different systems were analyzed and interpreted in terms of the particularities and chemical mechanisms involved in the different degradation processes, aiming at a better understanding of the fundamentals governing the processes.

Inúmeras são as vantagens da utilização de instrumentos rotatórios de níquel-titânio no preparo químico-cirúrgico, como por exemplo, melhor modelagem dos canais curvos e uma diminuição significativa no tempo de trabalho. Todavia, a maior preocupação no uso desses instrumentos tem sido a sua fratura, principalmente, por sua ocorrência estar ligada a diferentes fatores. O objetivo do presente estudo foi avaliar a influência da velocidade de rotação e do número de usos, no tempo de trabalho e na ocorrência de fraturas de instrumentos de dois sistemas rotatórios de níquel-titânio (K3 e RaCe), em canais simulados com mesmo ângulo de curvatura. Foram avaliados os instrumentos 25/.04 dos dois sistemas nas velocidades de 180, 350, 600 rpm ao instrumentarem 5 mm referentes à curvatura dos canais simulados. Para cada velocidade foram utilizadas limas com 1, 2 e 3 usos. Um contra-ângulo foi adaptado a um dispositivo calibrado para realizar movimentos padronizados de penetração nos canais simulados. Foram mensurados: o tempo necessário para instrumentar a curvatura do canal e a quantidade de fraturas ocorridas. Os resultados obtidos foram submetidos a ANOVA sendo em seguida empregado o teste de Tukey (&#945;=5%). Sob as condições desse experimento, o aumento da velocidade diminuiu o tempo de instrumentação em ambos os sistemas. Os instrumentos RaCe prepararam o canal em menor tempo do que os instrumentos K3 nas velocidades de 350 e 600 rpm (p<0,05), não havendo diferença em 180 rpm (p>0,05). Ocorreu maior número de instrumentos fraturados nas velocidades de 180 e 600 rpm para o sistema RaCe e de 600 rpm para o K3, e nenhuma fratura na velocidade de 350 rpm para ambos. O número de usos não influenciou o tempo de trabalho para nenhum sistema (p>0,05), porém, o número de fraturas aumentou proporcionalmente ao aumento do número de usos, exceto na velocidade de 350 rpm na qual não ocorreram fraturas. Os instrumentos RaCe apresentaram maior índice de fratura para a velocidade de 180 rpm (30%) do que para 600 rpm (13,33%). A velocidade de 350 rpm foi a mais segura para os instrumentos de ambos os sistemas. / Use of nickel-titanium rotary instruments has many advantages like better shaping of curved canals and lower working time. However, instrument fracture has always been a serious concern in root canal treatment because it involves a lot of factors. The aim of this study was to evaluate the influence of rotational speed and number of uses on the preparation time and incidence of fractures of K3 and RaCe instruments, using simulated root canals with the same angle of curvature. Nickel-titanium 25/.04- tapered instruments of both rotary systems were tested at 180, 350 and 600 rpm during shaping of 5 mm curvature’s extent. The files were used 3 times in each rotational speed. A contra-angle electric handpiece was mounted on a machine that was calibrated to deliver a constant penetration movement. Working time and incidence of fractures were measured. The results were analyzed statistically using a one-way analysis of variance with a post-hoc Tukey test (&#945;=5%). Under the conditions of this study, higher rotational speeds reduced preparation time for both rotary systems. RaCe instruments showed lower preparation time than K3 instruments at 350 and 600 rpm (p<0,05). There was no significant difference at 180 rpm (p>0,05). There was a higher incidence of fractures at 180 and 600 rpm for RaCe instruments and at 600 rpm for K3 instruments. No file breakage occurred at 350 rpm for both instruments. Preparation time was not influenced significantly by the frequency that the files were used (p>0,05). Incidence of fractures increased with an increase in the number of file usage, unless at 350 rpm in which none of the files fractured. At 180 rpm, RaCe instruments showed a higher incidence of breakage than at 600 rpm. Rotational speed of 350 rpm was the safest for both kind of instruments tested in this study.

Algoritmos computacionais e análise matemática têm sido grandes aliados na determinação de informação quantitativa extraída de observações experimentais. No presente trabalho, estudou-se a aplicação da metodologia do problema inverso em balanço populacional que descreve como varia a distribuição de tamanhos de moléculas poliméricas durante diferentes processos de degradação de polímeros. A evolução da distribuição durante o processo de quebra pode ser descrita matematicamente por equação de balanço populacional. No assim chamado problema inverso, as distribuições medidas experimentalmente são usadas para estimar os parâmetros do balanço populacional que descrevem, por exemplo, como as taxas de quebra variam ao longo do comprimento da cadeia e como variam com o tamanho da cadeia. Este problema inverso é conhecido por seu intrínseco mal condicionamento numérico. Um algoritmo previamente desenvolvido na literatura para problemas de quebra de gotas em emulsões líquidas, baseado no conceito de auto-similaridade das distribuições, foi adaptado e aplicado no presente trabalho para o problema de quebra de cadeias poliméricas durante a degradação do polímero. Dados experimentais de diferentes processos de degradação, obtidos da literatura, foram testados: degradação de polipropileno por radicais livres gerados por peróxidos, degradação de dextrana por hidrólise ácida, degradação ultra-sônica de dextrana, degradação mecânica por cisalhamento de poliestireno, degradação enzimática de guar, e degradação ultrassônica de guar. As distribuições de taxa de quebra obtidas para os diferentes sistemas foram analisadas e interpretadas em termos das particularidades e do mecanismo de cada tipo de processo de degradação, visando um melhor entendimento fundamental dos processos. / Computational algorithms are used to obtain quantitative information from experimental observations. The aim of the present work was the application of the methodology of inverse problem in population balance used to describe the evolution of the chain length distribution in different polymer degradation processes. The time evolution of the chain length distribution during the polymer breakage can be mathematically described by a population balance equation. In the so-called inverse problem, experimentally measured distributions are used to estimate the parameters of the population balance, such as the distribution of breakage rate along the chain and as function of the chain length. The inverse problem is known to be an ill-conditioned numerical problem. An algorithm previously developed in the literature for liquid droplet breakage in liquid emulsions, based on the concept of self-similarity of the distributions, was adapted and applied in the present work for the problem of polymer scission during polymer degradation. Experimental data of degradation of different polymers were taken from the literature and used to test the procedure: free-radical degradation of polypropylene acid hydrolysis of dextran, ultrasonic degradation of dextran, shear-induced mechanical degradation of polystyrene, enzymatic hydrolysis of guar; and ultrasonic degradation of guar. The breakage rate distribution obtained for the different systems were analyzed and interpreted in terms of the particularities and chemical mechanisms involved in the different degradation processes, aiming at a better understanding of the fundamentals governing the processes.

In this study, the effects of neutral particles addition on the breakage of wastewater flocs toimprove the efficiency of sonication pretreatment for UV disinfection process have been studied.Kaolin particles as a potentially useful material that is neutral, natural and cheap were added towastewater samples prior to sonication. Results obtained in this study indicated that hard andsmall kaolin particles do not have any significant effect on the particle breakage efficiency byultrasound. The addition of kaolin particles did not significantly increase the cavitation activity(as characterized by potassium iodide actinometry) either. These findings contradict earlierreports that neutral particles can act as nucleation sites and hence enhance cavitation intensity. Inthis work, sonication of wastewater samples for 60s in the absence of kaolin particles resulted inan approximately one log decrease in the number of surviving bacteria colonies at the tailinglevel and 1.4 log units increase at the initial slope of coliform removal in UV dose responsecurve, however addition of kaolin particles prior sonication did not significantly affect the UVdose response curve .The results presented in this study should be treated as preliminary andfurther detailed investigations are needed to better evaluate this issue.