High-quality Items Research Articles

Statistical classification for cognitive diagnostic assessment: an artificial neural network approach

The purpose of the current investigation was to describe how the artificial neural networks (ANNs) can be used to interpret student performance on cognitive diagnostic assessments (CDAs) and evaluate the performances of ANNs using simulation results. CDAs are designed to measure student performance on problem-solving tasks and provide useful diagnostic information about cognitive skill acquisition. But for CDA to realise its potential as a formative testing method, substantial progress must be made in the development of cognitive models that characterise students’ knowledge structures and processes skills, the construction of high-quality test items that precisely measure the nature of the knowledge and skills as specified in the cognitive models, as well as the advancement of psychometric techniques that allow us to accurately interpret student performance. The current investigation focuses on the third component as we examine the use of ANNs as a powerful nonparametric statistical method for diagnostic classification.

English

Now a days web plays an important role in the distribution of information from different sources to the users. The main problem that comes into play is called Information overloading where, search engines retrieve plenty of contents related to any keyword query that are provided by the users. Users prefer the fast retrieval of data while browsing the portals. Here comes the importance of content recommendation. Content recommendation helps to overcome information overloading problem by choosing the best matching contents. Thus users get better response without wasting their time. Most of the recommendation systems face various difficulties while identifying high quality items and providing this to users. So this is our motivation for conducting an analysis on content recommendation. Here we compare different methods for content recommendation.

Expertise in Online Markets

We examine the effect of the presence of expert buyers on other buyers, the platform, and the sellers in online markets. We model buyer expertise as the ability to accurately predict the quality, or condition, of an item, modeled as its common value. We show that nonexperts may bid more aggressively, even above their expected valuation, to compensate for their lack of information. As a consequence, we obtain two interesting implications. First, auctions with a “hard close” may generate higher revenue than those with a “soft close.” Second, contrary to the linkage principle, an auction platform may obtain a higher revenue by hiding the item’s common-value information from the buyers. We also consider markets where both auctions and posted prices are available and show that the presence of experts allows the sellers of high-quality items to signal their quality by choosing to sell via auctions. This paper was accepted by J. Miguel Villas-Boas, marketing.

The Alchian-Allen Theorem and the Economics of Internet Animals

The Alchian-Allen Theorem and the Economics of Internet Animals

Expertise in Online Markets

We examine the effect of the presence of knowledgeable buyers (experts) in online markets where auctions with a hard close and posted prices are widely used. We model buyer expertise as the ability to accurately predict the quality, or condition, of an item. In auctions with a hard close, sniping – submitting bids in the last minute – emerges as an equilibrium strategy for experts. We show that non-experts bid more aggressively as the proportion of experts increases. As a consequence, we establish that the auction platform may obtain a higher revenue by (i) enforcing a hard close and allowing sniping, and (ii) withholding information regarding the quality of the item. Moreover, in online markets where both auctions and posted prices are available, we show that the presence of experts allows the sellers of high quality items to signal their quality by choosing to sell via auctions.

Using Visibility to Control Collective Attention in Crowdsourcing

Online crowdsourcing provides new opportunities for ordinary people to create original content. This has led to a rapidly growing volume of user-generated content, and consequently a challenge to readily identify high quality items. Due to people’s limited attention, the presentation of content strongly affects how people al- locate effort to the available content. We evaluate this effect experimentally using Amazon Mechanical Turk and show that it is possible to manipulate attention to accomplish desired goals.

Influence of Food Resources on the Ranging Pattern of Northern Pig-tailed Macaques (Macaca leonina)

Food availability may influence primates’ home range size and use. Understanding this relationship may facilitate the design of conservation strategies. We aimed to determine how fruit availability influences the ranging patterns of a group of northern pig-tailed macaques (Macaca leonina) living around the visitor center of Khao Yai National Park, Thailand. We predicted that macaques would increase their range during low fruit abundance periods to gather high-quality food and that they would go where there are more fruits or more fruits of particular species. We also predicted that human food, linked to human presence, would attract the macaques. We followed the macaques and recorded their diet and movements within their home range. We superimposed a grid on kernels defining the monthly home range surface to compare spatially macaques’ travel and the availability of fruits measured on botanical transects. Our results showed that the macaques increased their monthly home range in March, probably to obtain newly available fruits. During high fruit abundance seasons, they spent more time near particular fruit species. In August and September, although fruits became rare again, macaques kept their home range large, perhaps to find enough fruits as supplies dwindled. Finally, from October to February, they decreased their monthly home range size while consuming human food, a high-quality item. In conclusion, the macaques used several ranging strategies according to fruit availability. However, we think that, without human food, macaques would tend to increase their range during low fruit abundance periods, as predicted.

Interest before liking: Two-step recommendation approaches

Recommender systems become increasingly significant in solving the information explosion problem. Existing techniques focus on minimizing predicted rating errors and recommend items with high predicted values to people. They consider high and low rating values as liking and disliking, respectively, and tend to recommend items that users will like in the future. However, especially in the information overloaded age, we consider whether a user rates an item as a measure of interest no matter whether the value is high or low, and the rating values themselves represent the attitude to the quality of the target item. In this paper, we propose two-step recommendation approaches that recommend items matching users’ interests first, and then try to find high quality items that users will like. Experiments using MovieLens dataset are carried out to evaluate the proposed methods with precision, recall, NDCG, preference-ratio and precision-like as evaluation metrics. The results show that our proposed approaches outperform the seven existing ones, i.e., UserCF, ItemCF, ALS-WR, Slope-one, SVD++, iExpand and LICF.

Lemon complaints: When online auctions go sour

"Lemon" complaints reveal that online auction experiences can turn sour. Theory on information asymmetry explains how "lemons" could drive high quality items away from a market leaving a dominance of poor quality goods. In this paper we analyze "lemon" complaints using content analysis and hierarchical logistic regression. In the data collection of 306 complaints from 8 product categories in online auctions, the results show that compared to standard products "lemons" are much more likely if the product category is for functional items, such as computers and consumer electronics; non-standard items with product description complexity, such as collectibles; and fragile items, such as pottery and glassware. Contrary to expectations, clothing and jewelry, representing sensory products, did not have a statistically significant impact on the frequency of "lemons". Although two seller negative feedback rating measures did predict non-receipt of goods, seller and buyer ratings and experience did not predict "lemons".

International assessment: A Rasch model and teachers' evaluation of TIMSS science achievement items

AbstractThe Trends in International Mathematics and Science Study (TIMSS) is a comparative assessment of the achievement of students in many countries. In the present study, a rigorous independent evaluation was conducted of a representative sample of TIMSS science test items because item quality influences the validity of the scores used to inform educational policy in those countries. The items had been administered internationally to 16,009 students in their eighth year of formal schooling. The evaluation had three components. First, the Rasch model, which emphasizes high quality items, was used to evaluate the items psychometrically. Second, readability and vocabulary analyses were used to evaluate the wording of the items to ensure they were comprehensible to the students. And third, item development guidelines were used by a focus group of science teachers to evaluate the items in light of the TIMSS assessment framework, which specified the format, content, and cognitive domains of the items. The evaluation components indicated that the majority of the items were of high quality, thereby contributing to the validity of TIMSS scores. These items had good psychometric characteristics, readability, vocabulary, and compliance with the assessment framework. Overall, the items tended to be difficult: constructed response items assessing reasoning or application were the most difficult, and multiple choice items assessing knowledge or application were less difficult. The teachers revised some of the sampled items to improve their clarity of content, conciseness of wording, and fit with format specifications. For TIMSS, the findings imply that some of the non‐sampled items may need revision, too. For researchers and teachers, the findings imply that the TIMSS science items and the Rasch model are valuable resources for assessing the achievement of students. © 2012 Wiley Periodicals, Inc. J Res Sci Teach 49: 1321–1344, 2012

Seasonal variation in feeding habits and diet selection by wild boars in a semi-arid environment of Argentina

The wild boar, Sus scrofa, was first introduced for hunting purposes in Argentina in 1906 and presently occupies a wide range of habitats. Understanding the food habits of invasive species is important for predicting the effects of animal food consumption on the environment and on human activities, such as farming. The wild boar is an omnivorous, opportunistic species whose diet is determined by the relative abundance of different types of foods. In general, the wild boar’s diet has been widely studied in the world, both as a native and invasive species, but little is known regarding food resource selection in the Monte Desert biome. Our study assessed the seasonal variation in the diet of wild boars, as well as the nutritional quality of consumed items. Further, we determined the diet selection of this species. Diet analyses were based on faecal samples collected over two seasons (wet and dry) in 1 year. Herbs were the most frequently consumed food item, with wild boars showing a selection for them in both seasons. The wild boar uses food resources according to seasonal availability (larger trophic niche breadth under higher plant diversity, as in the wet season). In turn, within each season, it selects items of high forage quality and high carbohydrate contents. In conclusion, this foraging strategy enables wild boar to maximize energy budget through food selection in order to survive in a semi-arid environment such as the Monte Desert.

When budgeting backfires: how self-imposed price restraints can increase spending

Abstract A common strategy for controlling spending is to impose a price restraint on oneself. For example, a consumer who is concerned with limiting expenses may decide before going shopping that he or she only wants to spend approximately $100 for a particular purchase. Although conventional wisdom predicts that self-imposed price restraints will decrease consumer spending, the authors show that salient price restraints can actually increase consumers' preferences for high-priced, high-quality items. The authors propose that making a price restraint salient has the effect of partitioning consumers' evaluations of price and quality, leading to larger differences in perceived quality between options and a greater focus on quality during the final decision. Thus, while budgets and other types of price restraints can limit spending by eliminating some high-priced options from consideration, this research suggests that they can also have the ironic effect of increasing consumers' spending relative to a situa...

When Budgeting Backfires: How Self-Imposed Price Restraints Can Increase Spending

A common strategy for controlling spending is to impose a price restraint on oneself. For example, a consumer who is concerned with limiting expenses may decide before going shopping that he or she only wants to spend approximately $100 for a particular purchase. Although conventional wisdom predicts that self-imposed price restraints will decrease consumer spending, the authors show that salient price restraints can actually increase consumers' preferences for high-priced, high-quality items. The authors propose that making a price restraint salient has the effect of partitioning consumers' evaluations of price and quality, leading to larger differences in perceived quality between options and a greater focus on quality during the final decision. Thus, while budgets and other types of price restraints can limit spending by eliminating some high-priced options from consideration, this research suggests that they can also have the ironic effect of increasing consumers' spending relative to a situation in which consumers have not imposed a price restraint.

Head-to-head comparisons of quality of life instruments for young adult survivors of childhood cancer

Few studies examine the relevance of health-related quality of life (HRQOL) instruments for young adult survivors of childhood cancer (YASCC). This study compared the psychometric properties of two survivor-specific instruments, the Quality of Life-Cancer Survivor (QOL-CS) and Quality of Life in Adult Cancer Survivor (QLACS). Data from 151 YASCC who enrolled in cancer/tumor registries of two medical centers were used. We examined construct validity by conducting confirmatory factor analysis using indices of chi-square statistic, comparative fit index, and root mean square error of approximation. We examined convergent/discriminant validity by comparing Pearson's correlation coefficients of homogeneous (e.g., physical functioning and pain) of both instruments versus heterogeneous domains (e.g., physical and psychological functioning). We assessed known-groups validity by examining the extent to which HRQOL differed by late effects and comorbid conditions and calculated relative validity (RV) defined as contrasting F-statistics of individual domains to the domain with the lowest F-statistic. Superior known-groups validity is observed if a domain of one instrument demonstrates a higher RV than other domains of the instruments. YASCC data cannot replicate the constructs both instruments intend to measure, suggesting poor construct validity. Correlations of between-homogeneous and between-heterogeneous domains of both instruments were not discernible, suggesting poor convergent/discriminant validity. Both instruments were equally able to differentiate HRQOL between YASCC with and without late effects and comorbid conditions, suggesting similar known-groups validity. Neither instrument is superior. Item response theory is suggested to select high-quality items from different instruments to improve HRQOL measure for YASCC.

Which Dress Do You Like? Exploring Brides’ Online Communities

Abstract To find the perfect wedding dress, a bride will consult bridal magazines, bridal fairs, family, and friends. Today’s bride might also watch popular television shows such as TLC’s, “Say Yes to the Dress,” or read and/or post comments on popular online wedding planning sites such as TheKnot.com, Weddingchannel.com, and Brides.com. According to Nelson and Otnes (2005), “Many brides use the Internet as a resource because it enables them to easily access information and communicate with widely dispersed providers of wedding resources” (p. 90). Nelson and Otnes (2005) found that many brides are participating in online virtual communities (i.e., Internet-based message boards) that “focus on the shared ritual and offer camaraderie and information exchange” (p. 90). In fact, the Bridal Association of America reported that 77% of brides in 2009 used the Internet to aid in the planning and/or purchasing of wedding related products and services. The purpose of this exploratory research is to investigate the ...

A Discrete Time Markov Chain Model for a Periodic Inventory System with One-Way Substitution

This paper studies the optimal design of an inventory system with “one-way substitution” , in which a high-quality (and hence, more expensive) item fulfills its own demand and simultaneously acts as backup safety stock for the (cheaper) low-quality item. Through the use of a discrete time Markov model we analyze the effect of one-way substitution in a periodic inventory system with an (R,s,S) or (R,S) order policy, assuming backorders, zero replenishment leadtime and correlated demand. In more detail, the optimal inventory control parameters (S and s) are determined in view of minimizing the expected total cost per period (i.e. sum of inventory holding costs, purchasing costs, backorder costs and adjustment costs). Numerical results show that the one-way substitution strategy can outperform both the “no pooling” (only product-specific stock is held, and demand can never be rerouted to stock of a different item) and “full pooling” strategies (implying that demand for a particular product type is always rerouted to the stock of the flexible product, and no product-specific stock is held)− provided the mix of dedicated and flexible inputs is chosen adequately − even when the cost premium for flexibility is significant. Furthermore, we can observe that decreasing the demand correlation results in rerouting more demand to the flexible product and because of the risk-pooling effect reduces the optimal expected total cost.

Parameter Estimation of the Raw Item in Computerized Adaptive Testing

Along with the development of computer technology and increasing needs of individual learning, Computerized Adaptive Testing (CAT) has received more and more attention. However, the problem of the test security is becoming a new challenge to the CAT, for example, excessive exposure of the test items might weaken the efficiency and equity of the CAT. Therefore, constructing a large-scale and high-quality CAT item bank is highly demanded The traditional method of constructing a CAT item bank involves four steps: first, the items are developed by the experts according to the test specification and blueprint; second, a representative sample of examinees is recruited to take the test; Then, the calibration of item parameters and testing of the model-data fit will be conducted afterward. Finally, items of high-quality and its item parameters will be added into the item bank based on the pre-analysis. However, several problems exist in the above traditional method. First, a large number of test takers are needed, which is time-consuming and expensive. Second, the security of the items cannot be guaranteed in the pilot test. Third, complicated techniques of equating may have to be used to construct a good item bank, which may also affect the security of the items, especially when the anchor items are repeatedly used in the test equating process. Thus, if the raw items can be seeded in the CAT process and the item parameters combined with the examinee abilities estimated at the same time, it will be significant for the construction of CAT item bank. The research in this area has not been widely conducted and reported in the domestic journals, although this issue has been a big topic for foreign researchers. Thus, This study aims to explore how to insert raw items and estimate the item parameters in CAT and investigate the efficient strategies with high security for enlarging the item bank. A new online calibration method is proposed based on the principle of adaption in CAT, provided there is a small-scale item pool. And the formula of initial value during the stage of the iteration is determined. When the ability parameter has been estimated, the conditional maximum likelihood estimation(CMLE) will be implemented to estimate item parameters in the raw items. First, the difficulty parameter could be obtained through CMLE. Second, the discrimination parameter could be estimated with the abilities and difficulty parameter and the initial value of the discrimination parameter could be gained through CMLE. Third, the difficulty parameter could be estimated when the discrimination parameter and abilities are known .Repeat the second and the third steps until the stop condition is satisfied. Simulation of Monte Carlo has been employed to estimate the parameters of raw items with the one-parameter Logistic and two-parameter Logistic models in the study and good result has been gained.

Montreal Museum of Fine Arts, Collections of Mediterranean Antiquities, Vol.2: The Terracotta Objects (review)

Reviewed by: Montreal Museum of Fine Arts, Collections of Mediterranean Antiquities, Vol.2: The Terracotta Objects Lucilla Burn E.P. Zoïtopoúlou, B. Caron, A. Deblois, Montreal Museum of Fine Arts, Collections of Mediterranean Antiquities, Vol.2: The Terracotta Objects. Leiden: Brill, 2010. Pp. xl + 136. €108;US $154. ISBN 9789004183063. This is the second volume in a projected series of publications of the Mediterranean antiquities in the Montreal Museum of Fine Arts. The series is organised by material: volume 1 was devoted to ancient glass and the current volume presents non-pottery objects made of clay. These consist of 42 clay lamps (plus two bronze examples), 21 terracotta figures or fragments of figures, and one terracotta arula or miniature altar. Both the catalogue entries and the introductory material are bilingual, with parallel texts in English and French. The introductory sections offer a brief discussion of the origins of the collection, followed by concise but generally helpful accounts of the technology involved in forming and decorating lamps or figurines, their forms and functions. The main part of the volume is occupied by the catalogue entries. Most of these are very spaciously laid out, occupying a double-page spread with one or more, large, generally clear (if regrettably still black and white) photographs and, where appropriate, drawings on one side, and texts on the other. The catalogue texts provide information on find-spots, where known, technical details such as dimensions and clay colour (with scrupulous reference to Munsell soil colour charts), parallels and discussion. The bibliography is extensive and generally thorough. The English phraseology is at times slightly baffling—few people would understand what is meant by "the main lemma" (xxix); in English tortoises have feet, not paws (terracotta no.5 [101]); nor is it clear why in the description of the ephedrismos group (terracotta 15 [121]) the Eros is described as "not yet a girl". Occasionally the French text seems to contain more detail than the English—if the nine holes pierced in lamp 10 are "trous d'évent" (air holes), it would be nice for English readers to be told [End Page 284] this too (but see Bailey [1975] for an acknowledgment that such holes are puzzling and an interesting brief discussion of their possible function1). If the term "pappas type" is to be used for terracottas 6 and 7, or "Herodian" for lamp 19, it is surely desirable to explain the origin of these, by now, rather esoteric terms; and though lamp 30 is referred to in the introduction (xviii) as an example of African red slip ware, this fact is not really made clear in the catalogue entry itself (63). In terms of the illustrations, while these are mainly clear, the inclusion of a scale would have been useful, and the printing of some of them is rather light in tone. One has to take on trust, for example, the six breasts of the fragment of the torso of the Aphrodite of Ephesus (terracotta 18 [124]). There are places, too, where it seems that more rigorous proof-checking was needed. In the case of terracotta 19, for example, the figure of a standing boy from Egypt, the reader is referred for a parallel to "Bailey, 1988, Q1992 EA, pl.39. (Plastic lamp from the same mould)." But looking up this reference (to vol. iii of the British Museum Catalogue of Lamps), as a "standing boy lamp" sounds rather intriguing, Q1992 is found to be a completely unrelated type, a lamp surmounted by a bust of Athena, complete with helmet. Nor are there any examples of "standing boy" lamps either on plate 39 or elsewhere in this volume. There are several occasions on which one would wish for more—or indeed any—discussion in the "discussion" sections of the catalogue entries: for example, there is plenty that could be said about the symbolic status of the fine geometric horse (figurine 1). This collection contains some high quality items that deserve to be better known, but its cataloguers seem all too reticent about voicing or sharing their views. They have clearly recognised the star quality of the ephedrismos group (terracotta 15), for example, which appears in colour...

Polyhedral analysis for the two-item uncapacitated lot-sizing problem with one-way substitution

We consider a production planning problem for two items where the high quality item can substitute the demand for the low quality item. Given the number of periods, the demands, the production, inventory holding, setup and substitution costs, the problem is to find a minimum cost production and substitution plan. This problem generalizes the well-known uncapacitated lot-sizing problem. We study the projection of the feasible set onto the space of production and setup variables and derive a family of facet defining inequalities for the associated convex hull. We prove that these inequalities together with the trivial facet defining inequalities describe the convex hull of the projection if the number of periods is two. We present the results of a computational study and discuss the quality of the bounds given by the linear programming relaxation of the model strengthened with these facet defining inequalities for larger number of periods.

Low reproductive success of great tits in the preferred habitat: A role of food availability

Habitat-related variation has been revealed in the seasonal reproductive patterns of great tits inhabiting mosaics of deciduous woodland fragments and managed coniferous forests. The number and quality of offspring tend to be higher in the non-preferred coniferous habitat compared with the preferred deciduous habitat. We explored whether these patterns can be explained by variation in food abundance and/or parental provisioning ability. Frass fall seemed not to be a reliable measure of the seasonal dynamics of nestling feeding conditions, although it is widely used for this purpose. No habitat-related differences were found in the tendency of parents to increase provisioning frequency in response to increased hunger levels of nestlings, suggesting that provisioning frequency as such is not a limiting factor for nestling growth. Higher feeding rates in deciduous habitat were associated with lower proportions of high-quality food items among prey delivered to offspring. These findings confirm that relatively high nestling feeding rates in birds may reflect the low quality of available food rather than the quality of parental care or an abundance of food in the environment. The results also indicate that deciduous forest habitat, though preferred by tits, may sometimes provide poorer brood-rearing conditions than the non-preferred, coniferous habitat. We suggest that the great tit's preference for deciduous habitat, which presumably evolved in more southern regions, may be maladaptive in northern regions where deciduous woods are mainly young, secondary stands of alder and birch.