Verification And Validation Research Articles

Validating human induced pluripotent stem cell-specific quality control tests for the release of an intermediate drug product in a Good Manufacturing Practice quality system

One of the challenges in Good Manufacturing Practice (GMP)-compliant human induced pluripotent stem cell (hiPSC) production is the validation of quality control (QC) tests specific for hiPSCs, which are required for GMP batch release. This study presents a comprehensive description of the validation process for hiPSC-specific GMP-compliant QC assays; more specifically, the validation of assays to assess the potential presence of residual episomal vectors (REVs), the expression of markers of the undifferentiated state and the directed differentiation potential of hiPSCs. Critical aspects and specific acceptance criteria were formulated in a validation plan prior to assay validation. Assay specificity, sensitivity and reproducibility were tested, and the equipment used for each assay was subjected to performance qualification. A minimum input of 20 000 cells (120 ng of genomic DNA) was defined for accurate determination of the presence of REVs. Furthermore, since vector loss in hiPSC lines is a passage-dependent process, we advocate screening for REVs between passages eight and 10, as testing at earlier passages might lead to unnecessary rejection of hiPSC lines. The cutoff value for assessment of markers of the undifferentiated state was set to the expression of at least three individual markers on at least 75% of the cells. When multi-color flow cytometry panels are used, a fluorescence minus one control is advised to ensure the control for fluorescent spread. For the assay to assess the directed differentiation potential, the detection limit was set to two of three positive lineage-specific markers for each of the three individual germ layers. All of our assays proved to be reproducible and specific. Our data demonstrate that our implemented analytical procedures are suitable as QC assays for the batch release of GMP-compliant hiPSCs.

Validation of the Revised Systems Thinking Measuring Instrument(Re_STMI) for High School Students

The purpose of this study is to verify the validity of the revised STMI, which is a revised and supplemented version of the Systems Thinking Measuring Instrument (STMI) developed by Lee et al. (2013) for high school students. For this purpose, we used data from 475 high school students' responses to 20 Revised STMI questions and 20 STS scale questions. Validity verification includes item response analysis (Item Reliability, Item Map, Infit and Outfit MNSQ, and DIF of male and female groups), exploratory factor analysis (main axis factor analysis using Promax), and confirmatory factor analysis using structural equation model. And central/cross validity verification and correlation analysis between the two scales were used. The research results are as follows. First, as a result of the item response analysis of the Revised STMI 20 questions, Item Reliability was .98 and Infit MNSQ was .84~1.39, and valid results were also analyzed in Item Map and DIF analysis. Second, in the exploratory factor analysis, all sub-questions of the five sub-factors showed factor loading values of .3 or higher, and the reliability of each factor was .631~.800 and the overall reliability was .863. Third, in the confirmatory factor analysis, all model fit values were good (χ2/df: 2.406, CFI: .923, TLI: .908, SRMR: .046, RMSEA: .054), and the convergent validity and crossvalidity were also established. The results showed that the model was suitable. Lastly, in the correlation analysis with the 20 items of the STS scale, the correlation between all items was .754, and the correlation with STS items for each sub-factor was high, ranging from .426 to .658. Therefore, in the case of the Revised STMI, significant results were obtained not only in construct validity but also in official validity, and the results of this study showed improved validity results compared to research results using existing scales. Continuously, additional validation research should be conducted so that the Revised STMI can be applied to various groups, including not only high school students, but also elementary and middle school students, and college students. In addition, ongoing research on the relationship between system thinking and other learning-related measures should be actively conducted using validated instrument.

지속가능발전교육(ESD)에 기반한 유아 텃밭활동 프로그램 개발

This study was conducted to foster the essential capacities for coexistence between humans and nature, in order to achieve sustainable development. The “Children's Garden Activity Program Based on Education for Sustainable Development (ESD)” was implemented following prior research and literature review, early childhood teachers' perception, actual status and needs survey, in-depth interviews, expert content validity verification, and field application feasibility verification stages. A preliminary version was created. The finalized “Children's Garden Activity Program Based on Education for Sustainable Development (ESD)” was designed to efficiently integrate Education for Sustainable Development (ESD) and holds significance in the following aspects. First, the four core values of development, including respect development—respect for humans for the future for cultural diversity, for diversity. development. The educational content for each session was developed in alignment with the Sustainable Development Goals (SDGs) established by the United Nations. Thirdly, the teaching-learning approach was segmented into teaching-learning phases and teaching methods, encompassing a total of 15 sessions. Following the development of the program, the field applicability and validity of the content were confirmed through evaluations by children and teachers.

행위자-네트워크 이론(Actor- Network Theory)을 활용한 초등교사의 발명 단원 교재 연구 모습의 이해

This study explores the socio-material network associated with elementary school teachers’ invention unit textbooks through the lens of Actor-Network Theory. Using a qualitative case study method, the research process involved basic research, interviewer selection, data collection, data analysis, and a summary of the results. The subjects were selected through purposive sampling, and the interview questions covered six areas: class focus, class community, media use, teacher experiences, curriculum restructuring, and class environment creation. Intraclass Correlation Coefficient (ICC) verification and content validity verification were conducted. The data comprised transcribed interviews, which were analyzed via open coding and visualized as an Actor-Network Map. The results of this study are as follows. First, the study analyzed elementary school teachers' research on invention unit textbooks through an actor-network theoretical perspective, visualizing results through an Actor-Network Map. In the spaces of prescription and spaces of negotiation, various actors, including teachers who were the Obligatory Passage Point (OPP), were forming a network called “Textbook Research.” Second, based on the Actor-Network Map, the study analyzed the unique characteristics and significance of elementary school teachers’ research on invention unit textbooks. Actors were found to occasionally strengthen or weaken the cohesion of the network “Textbook Research” while also attracting other actors into the network. This study confirms that research on invention unit textbooks is not solely a measure of teacher competency but a complex web of relationships involving various non-human substances such as humans, objects, technologies, and institutions. In addition, it highlights the need for a more comprehensive understanding of invention education by examining the research on invention unit textbooks using various theories.

평화교육 수업 설계 모형 개발

Objectives The purpose of this study is to develop a peace education model that can be flexibly applied to diverse learners and diverse educational contexts.
 Methods Components of the peace education model were derived through a literature review. Based on this, a model was designed, and the designed model went through a validity verification process through formative research methods. For internal validation, I consulted with four experts who majored in education, and for external validation, I evaluated the usability of seven peace education practitioners and looked at learner responses in the educational field. Through this process, the model was modified and supplemented.
 Results The final model, which went through internal and external validation processes, was found to be valid. The peace education class design model developed in this study aims to 'cultivate peace sensitivity' and 'practice in life', starting with 'forming peace relationships', 'safe space', 'attitude open to various perspectives', ‘Ability to start anew’ is a content element. And the operating methods are education about peace (understanding), education for peace (application), and education by peace (acquisition).
 Conclusions This study presents a peace education class design model that can be used and applied in peace education fields. The peace education class design model developed in this study has a limitation in that the scope and level of use may vary depending on the instructor's understanding and experience of peace education and the educational environment.

Pathways to IEC Standards for Heliostat Design Qualification and Site Acceptance in Central Receiver CSP Applications

This paper surveys the existing landscape of standards relevant to heliostats, identifies their gaps, and proposes a path forward to a comprehensive set of heliostat guidelines, technical specifications, and standards under the framework of International Electrotechnical Commission (IEC) TC 117. Gaps in existing guidelines and standards are surveyed using a three-tiered taxonomy: component-level, heliostat-level, and field-level. At each level, the gap analysis is followed by a proposal for a coordinated path forward on the development of standards. At the component level, advances in the understanding of wind loading should inform a technical specification for drives and structures. Reflectors require consolidation of measurement guidelines into existing standards documents. Communications & controls require technical standards to inform their selection and secure implementation. At the heliostat level, IEC 62817 (solar trackers) adequately characterizes drive systems, structures, and electronics, but requires adaptation to heliostats’ use patterns, operating modes, and expected life cycles. IEC 62817 does not address heliostat beam quality and pointing accuracy, but the process for determining both is elaborated in the SolarPACES Guideline for Heliostat Performance Testing. This SolarPACES document requires two main modifications: adaptation to IEC language and inclusion of testing after heliostats which have undergone accelerated weathering and mechanical cycling (to understand performance degradation). At the field level, IEC 62862-4-2 addresses the function and control of heliostat fields but does not cover the statistically rigorous testing of heliostat groups, or field performance factors like security and soiling. The addition of documents under IEC-62862-4 is proposed to address this gap.

중등 과학영재의 창의성 평가 루브릭 개발

Objectives The purpose of this study is to develop a creativity evaluation rubric for secondary science gifted students.
 Methods To this end, first, the factors of creativity of science gifted students were extracted through related literature research. Second, after reviewing the content feedback through the expert council, it was confirmed by revising and supplementing it. Third, in determining the type of rubric, the general rubric and the analytical rubric were selected for the task, and the number of evaluation scales was four levels, and the qualitative expression of the evaluation scale was composed. Fourth, the performance level description for each scale based on the evaluation criteria was composed of four scales, and the objectivity of the performance criteria was secured by a qualitative statement method. Fifth, in September 2022, the first completed rubric was applied to the class for 20 second-year students of Dongnae Gifted Middle School, and revision and supplementation were conducted through the expert council. Sixth, after reviewing the content validity through the expert council using the meta-rubric, the CVI index for the meta-rubric was calculated for the science gifted education experts. Seventh, for the application of the rubric and the verification of reliability, classes were conducted for 20 second-year students of the Dongnae Gifted Education Center in November 2022, and the consistency statistics (PA) and Kappa coefficients were calculated by observing and evaluating the raters.
 Results As a result of the study, first, the extraction of creativity factors for science gifted and the setting and determination of evaluation criteria could be finally extracted into 4 affective areas and 9 cognitive areas. Second, the general and analytical rubric were selected for the determination of the rubric type, and the number of evaluation scales was determined to be 4, and the qualitative statement method was adopted. Third, it was possible to finally develop a creativity evaluation rubric for the middle school underprivileged through the application, modification, and supplementation of the rubric class, content validity verification, and reliability verification.
 Conclusions Such research results can be seen as meaningful in that the creativity evaluation rubric of secondary science gifted students was developed as a rubric that can be evaluated reasonably and objectively and can be used for more diverse science-related classes.

The defect sensitivity of brittle truss-based metamaterials

Architected strut-based metamaterials fabricated via three-dimensional printing exhibit a wide range of geometric and material heterogeneity, including variations in strut size, surface roughness, embedded micro-cracks and disconnected struts. The locations and severity of these defects are highly variable; combined with the complexity of the structure itself, it is exceedingly difficult to identify critical defects that limit performance and inform qualification protocols. To address this challenge, we consider the impact of distributions of defects for various strut-based lattice topologies. The role of defects is analyzed using Weibull distributions of strut failure strains. We relate the statistical distributions of strut properties to macroscopic stress-strain performance, using high through-put finite element predictions in thousands of virtual tests. Increasing the prevalence of defects decreases macroscopic strength; however, this has the complementary effect of introducing apparent ductility, i.e. load capacity even after the onset of strut failures. Hence, there is a trade-off between achieving high strength and gradual loss of stiffness that is desirable for thermal loading or lattice cores. Predictions of average strength as a function of Weibull modulus provide knock-down factors relative to the defect-free strength. In turn, these clearly identify quantitative processing targets to mitigate the impact of defects.

Validation of an automated dispensing system for subsequent dose dispensing of different radionuclides

BackgroundAutomated dispensing systems (ADSs) for radiopharmaceuticals have been developed to reduce the radiation exposure of personnel, to improve the accuracy of the dispensed dose and to limit the microbiological contamination. However, before implementing such systems, validation according to various applicable guidelines is necessary to ensure safety and quality. Here we present the selection, validation and implementation of the PT459R2 from manufacturer Lynax s.r.o. as a guidance protocol for validation according to GMP and GRPP guidelines. Validation included linearity accuracy and precision of the internal scintillation detector for different isotopes and microbiological validation for aseptic procedures.ResultsThe ADS can dispense accurate doses in the following linear range: 1000–10,000 MBq for lutetium-177, 20–74 MBq for zirconium-89, 100–1000 MBq for gallium-68 and 100–2000 MBq for fluorine-18. The maximum bias is 2.35% and the maximum coefficient of variation is 3.03% which meets the acceptance criteria of < 5%. Furthermore, the ADS does not affects the GMP class A environment in a laminar airflow cabinet and can dispense aseptically. In addition, radiation exposure is acceptable and data integrity is preserved.ConclusionThe PT459R2 ADS met all the requirements from our performance qualification and is therefore suitable for daily routine use in our center. Our approach can be used as a guidance for PQ of an ADS in a Radiopharmacy according to GMP and GRPP guidelines.

Collecting and Organizing the Influencing Factors of Team Communications to Handle Nuclear Power Plant Emergencies

A nuclear power plant (NPP), as a complex safety-critical system, requires qualified operators working in teams. Interactions between operators in the main control room (MCR) team are important to ensure safe operation. Since communication is the basis of the operators’ interactions, team communication is a significant factor affecting teamwork performance. Especially during NPP emergencies, poor team communication may lead to incorrect decisions and countermeasures, causing deterioration toward accidents. Moreover, in an emergency situation, emergency response teams are assembled. This multi-team and critical work condition further emphasizes the need for effective and accurate team communication. We collected the factors influencing team communication in NPP emergencies using a literature review combined with text mining. Our method for extracting the influencing factors consists of four steps; then, by applying topic modeling from text mining, we complemented the influencing factors. The resulting list of influencing factors of team communications for handling NPP emergencies is organized into five elements: individual, team, communication, NPP tasks, and external elements. Discussions on the team communication model, applicability, communication errors, and emergency response teams are also presented.

연구실 안전 분위기 측정도구 개발 및 타당화

Recently, accidents have been occurring continuously in domestic research labs, and in order to prevent them, the safety field is emphasizing the creation of a safe climate. Therefore, in this study, before confirming the role and performance of safety climate, we establish the definition and sub-factor of the concept of safety climate and develop a tool to measure it. Through this, we hope to contribute to revitalizing research on lab safety climate and related variables. Through previous research, a draft of the sub-factors and questions of the measurement tool was developed, and the measurement tool was validated through an expert content validity survey, preliminary survey, and main survey. The survey was conducted targeting people engaged in research activities, the measurement tool was validated through exploratory and confirmatory factor analysis, and the reliability of the measurement tool was secured through reliability analysis. In addition, correlation analysis with safety-related variables was conducted. The safety climate measurement tool was drafted with a total of 4 areas and 19 questions, and a total of 16 questions were selected as preliminary questions through verification of content validity. As a result of conducting a preliminary survey and conducting exploratory factor analysis, a total of 4 sub factor and 12 questions were converged. Afterwards, as a result of confirmatory factor analysis through this survey, the measurement tool was found to be valid, and there was a correlation with various safety related variables. The lab safety climate measurement tool consists of four sub-factor : lab operation policy, lab safety regulations, lab safety education, and communication between members, and was developed with a total of 12 questions. The correlation between safety related variables such as safety leadership, safety knowledge, safety attitude, and safety behavior was found to be significant, so it can be used in future lab safety related research and is expected to revitalize research.

초등학생의 진로장벽 검사도구 개발 및 타당화

Objectives This study was to systematically develop a Career Barrier Inventory(CBI) for upper elementary school students and verify its validity.&#x0D; Methods The concept of the career barriers were defined and sub-factors of the career barriers were derived based on the monistic view limited to contextual barriers(Lent et al., 1994/2000) and related previous studies. Preliminary items were developed through previous studies. And a preliminary scale of 27 items was developed through the expert’s content validity verification and the subjects’ understanding of the prior items. A preliminary survey was conducted targeting upper grades of elementary school students nationwide, and 136 of the collected data were used for exploratory factor analysis. The main survey sampled a different group from the preliminary survey across the country, and 236 (94.4%) of the collected data were used in CFA, through which the optimal CBI for elementary school students was developed and a systematic validation procedure was performed.&#x0D; Results The Major results were as follows; First, through EFA using preliminary survey data, four latent factor were validly extracted and reliability was secured. Second, as a result of CFA using the main survey data, three items with a standardized regression weights(β) of .50 or less were removed and the goodness of fit index for the final CBI measurement model (24 items) were reviewed, and all were good. Third, as a result of calculating the AVE and C.R., of each sub-factor, all of the evaluation criteria were satisfied and the construct validity was verified. Fourth, as a result of conducting a correlation analysis based on social support, self-esteem and self-efficacy measure-ment tools to verify criterion validity, the correlations among sub-factors of each variable were all significant. And the overall the reliability (Cronbach’s α) of the final CBI, was found to be .912, and the reliability of each sub-factor was also confirmed to be good.&#x0D; Conclusions Based on the monistic career barriers advocated in Social Cognitive Career Theory, the concept and sub-factors of career barriers for upper grades of elementary school students were identified and a CBI for upper grades of elementary school students whose reliability and validity were verified through systematic procedure was developed.

ICH Q14-inspired novel approach to establish an SFC-based purity method for carbamazepine.

The proposed ICH Q14 guideline "Analytical procedure development" describes science and risk-based approaches for development and maintenance of analytical procedures suitable for the assessment of the quality of drug substances and drug products. As a case study, the systematic development and validation of a supercritical fluid chromatography (SFC)-based purity method for carbamazepine is presented. Systematic analytical quality by design (AQbD) principles were applied using the software package Fusion QbD to the method development approach. The relationship between chromatographic parameters and the responses of interest were examined to improve the reliability of the method by understanding, reducing, and controlling sources of variability. Method performance qualification in terms of method robustness was finally carried out with the parameters that were classified as critical after method development and a validation study met previously set acceptance criteria. The developed SFC purity method for carbamazepine demonstrated readiness as a viable alternative to the official HPLC method published in the Ph.Eur. with improved peak resolution, improved peak symmetry, and faster analysis times (3min vs. 80 min for the official method). Its inherent reliability illustrates the superiority of AQbD in method development and application for drug quality assurance.

Soil electrical conductivity as a proxy for enhanced weathering in soils

To effectively monitor and verify carbon dioxide removal through enhanced weathering (EW), this study investigates the use of soil electrical conductivity (EC) and volumetric water content (θ) as proxies for alkalinity and dissolved inorganic carbon (DIC) in soil water. EC-θ sensors offer a cost-effective and straightforward alternative to traditional soil and water sampling methods. In a lab experiment, three different substrates were treated with NaHCO3 solutions to increase the alkalinity of the soil water and analyze the response. The combination of EC and θ to track the increase in carbonate alkalinity due to EW, and therefore CO2 consumption, is applicable for low cation exchange capacity (CEC) soil-substrates like the used quartz sand. However, the presence of organic material and pH-dependent CEC complicates the detection of clear weathering signals in soils. In organic-rich and clay-rich soils, only a high alkalinity addition has created a clear EC signal that could be distinguished from a non-alkaline baseline with purified water. Cation exchange experiments revealed that the used soil buffered alkalinity input and thereby might consume freshly generated alkalinity, initially mitigating CO2 uptake effects from EW application. Effective CEC changes with pH and pH buffering capacity by other pathways need to be considered when quantifying the CO2 sequestration potential by EW in soils. This should be estimated before the application of EW and should be part of the monitoring reporting and verification (MRV) strategy. Once the soil-effective CEC is raised, the weathering process might work differently in the long term.

Theoretical Studies on the Quantitative Structure-Toxicity Relationship of Polychlorinated Biphenyl Congeners Reveal High Affinity Binding to Multiple Human Nuclear Receptors.

Polychlorinated biphenyls (PCBs) are organic chemicals consisting of a biphenyl structure substituted with one to ten chlorine atoms, with 209 congeners depending on the number and position of the chlorine atoms. PCBs are widely known to be endocrine-disrupting chemicals (EDCs) and have been found to be involved in several diseases/disorders. This study takes various molecular descriptors of these PCBs (e.g., molecular weight) and toxicity endpoints as molecular activities, investigating the possibility of correlations via the quantitative structure-toxicity relationship (QSTR). This study then focuses on molecular docking and dynamics to investigate the docking behavior of the strongest-binding PCBs to nuclear receptors and compares these to the docking behavior of their natural ligands. Nuclear receptors are a family of transcription factors activated by steroid hormones, and they have been investigated to consider the impact of PCBs on humans in this context. It has been observed that the docking affinity of PCBs is comparable to that of the natural ligands, but they are inferior in terms of stability and interacting forces, as shown by the RMSD and total energy values. However, it is noted that most nuclear receptors respond to PCBs similarly to how they respond to their natural ligands-as shown in the RMSF plots-the most similar of which are seen in the ER, THR-β, and RAR-α. However, this study is performed purely in silico and will need experimental verification for validation.

Ongoing Analytical Procedure Performance Verification Using a Risk-Based Approach to Determine Performance Monitoring Requirements.

The analytical procedure life cycle (APLC) provides a holistic framework to ensure analytical procedure fitness for purpose. USP's general chapter <1220> considers the validation activities that take place across the entire analytical procedure lifecycle and provides a three-stage framework for its implementation. Performing ongoing analytical procedure performance verification (OPPV) (stage 3) ensures that the procedure remains in a state of control across its lifecycle of use post validation (qualification) and involves an ongoing program to collect and analyze data that relate to the performance of the procedure. Knowledge generated during stages 1 (procedure design) and 2 (procedure performance qualification) is used as the basis for the design of the routine monitoring plan to support performance verification (stage 3). The extent of the routine monitoring required should be defined based on risk assessment, considering the complexity of the procedure, its intended purpose, and knowledge about process/procedure variability. The analytical target profile (ATP) can be used to provide or guide the establishment of acceptance criteria used to verify the procedure performance during routine use (e.g., through a system/sample suitability test (SST) or verification criteria applicable to procedure changes or transfers). An ATP however is not essentially required to perform OPPV, and a procedure performance monitoring program can be implemented even if the full APLC framework has not been applied. In these situations, verification criteria can be derived from existing validation or system suitability criteria. Elements of the life cycle approach can also be applied retrospectively if deemed useful.

Vision-Based Hand Rotation Recognition Technique with Ground-Truth Dataset

The existing question-and-answer screening test has a limitation in that test accuracy varies due to a high learning effect and based on the inspector’s competency, which can have consequences for rapid-onset cognitive-related diseases. To solve this problem, a behavioral-data-based screening test is necessary, and there are various types of tasks that can be adopted from previous studies, or new ones can be explored. In this study, we came up with a continuous hand movement, developed a behavioral measurement technology, and conducted validity verification. As a result of analyzing factors that hinder measurement accuracy, this measurement technology used a web camera to measure behavioral data of hand movements in order to lower psychological barriers and to pose no physical risk to subjects. The measured hand motion is a hand rotation that repeatedly performs an action in which the bottom of the hand is seen in front. The number of rotations, rotation angle, and rotation time generated by the hand rotation are derived as measurements; and for calculation, we performed hand recognition (MediaPipe), joint data detection, motion recognition, and motion analysis. To establish the validity of the derived measurements, we conducted a verification experiment by constructing our own ground-truth dataset. The dataset was developed using a robot arm with two-axis degrees of freedom and that quantitatively controls the number, time, and angle of rotations. The dataset includes 540 data points comprising 30 right- and left-handed tasks performed three times each at distances of 57, 77, and 97 cm from the camera. Thus, the accuracy of the number of rotations is 99.21%, the accuracy of the rotation angle is 91.90%, and the accuracy of the rotation time is 68.53%, making the overall rotation measurements more than 90% accurate for input data at 30 FPS for measuring the rotation time. This study is significant in that it not only contributes to the development of technology that can measure new behavioral data in health care but also shares image data and label values that perform quantitative hand movements in the image processing field.

Assessment of land use cover changes, carbon sequestration and carbon stock in dry temperate forests of Chilas watershed, Gilgit-Baltistan

Abstract Land use and land cover change are affecting the global environment and ecosystems of the different biospheres. Monitoring, reporting and verification (MRV) of these changes is of utmost importance as they often results in several global environmental consequences such as land degradation, mass erosion, habitat deterioration as well as micro and macro climate of the regions. The advance technologies like remote sensing (RS) and geographical information system (GIS) are helpful in determining/ identifying these changes. In the current study area, changes in carbon stocks, notably in forest areas, are resulting in considerable dynamics of carbon stocks as a result of climate change and carbon sequestration. This study was carried out in the Diamer district of the Gilgit Baltistan (GB) Pakistan to investigate the change in cover change/land use change (particularly Forest Land use) as well as carbon sequestration potential of the forests in the district during almost last 25years. The land cover, temporal Landsat data (level 1, LIT) were downloaded from the USGS EROS (2016), for 1979-1989, 1990-2000 and 2001-2012. Change in land uses, particularly forest cover was investigated using GIS techniques. Forest inventory was carried out using random sampling techniques. A standard plot of size 0.1 ha (n=80) was laid out to determine the tree density, volume, biomass and C stocks. Simulation of C stocks was accomplished by application of the CO2FIX model with the data input from inventory. Results showed a decrease in both forest and snow cover in the region from 1979-2012. Similarly decrease was seen in tree volume, tree Biomass, dynamics of C Stocks and decrease was in occur tree density respectively. It is recommended we need further more like project such as BTAP (Billion Tree Afforestation Project) and green Pakistan project to increase the forest cover, to control on land use change, protect forest ecosystem and to protect snow cover.

VALIDATION OF COMPUTER SIMULATION OF COMPLEX THERMAL TRANSPORT PROBLEMS: A TRIBUTE TO PROFESSOR DARRELL PEPPER

An important consideration in mathematical modeling and numerical simulation is that of validation of the models. This is particularly critical in thermal systems and processes because of the simplifications and idealizations usually needed to make the problem amenable to a solution, lack of accurate material property data, combined mechanisms, uncertainty in boundary conditions, and other complexities in the process. Modeling is needed for a basic understanding of the processes involved, as well as for providing accurate inputs for system design, control, and optimization. However, it is important to ensure that the numerical code performs satisfactorily for the chosen method and that the model is an accurate representation of the physical problem. These aspects are sometimes referred to as verification and validation, respectively, or simply as validation of the mathematical/numerical model employed. Unless the models are satisfactorily validated and the accuracy of the predictions established, the models cannot be used as basis for design and for choosing operating conditions to obtain desired system or product characteristics. Validation of the models is based on a consideration of the physical behavior of the results obtained, elimination of the effects of arbitrary parameters like grid and time step, comparisons with available analytical or numerical results for similar problems, and comparisons with experimental results on a physical model or a prototype. This paper considers some of the major considerations involved in validation of numerical simulation models for complex thermal problems. A few examples of practical problems are also presented. This topic is chosen because it was of particular interest to Professor Darrell Pepper and the author has had several interactions with him on complex thermal problems.

Comparison of risk of recidivism among sexual offenders with and without sexual preference disorders using the STATIC-99R instrument.

The STATIC-99 instrument is one of the tools used for the assessment of the risk of recidivism, in line with the actuarial approach. One of the risk factors indicated by the scientific literature as having the greatest significance is sexual preference disorder. The aim of the study was to verify whether sexual offenders diagnosed with sexual preference disorders have a higher risk of recidivism. The study also aimed to present, for the first time in Poland, a quantitative scoring of individual risk factors in STATIC-99R and their prevalence, allowing for the verification of the theoretical validity of the STATIC-99R instrument in the analysis of the population of sexual offenders in Poland. The study material consisted of 100 court and penitentiary files of perpetrators of crimes against sexual freedom from 11 Polish penal institutions and remand centers. We used the STATIC-99R to evaluate each case. The distribution of the individual STATIC-99R risk factors in the population of the Polish sexual offenders is presented. The diagnosis of sexual preference disorders had no influence on the total STATIC-99R score but was associated with its individual factors. It can be concluded that the theoretical validity of the STATIC-99R tool is also relevant to the Polish study population and may be used in clinical practice.