Optimization of some factors affecting the performance of query expansion     

Young Mee Chung  Jae Yun Lee 《Information processing & management》2004,40(6):29

This paper examines the factors affecting the performance of global query expansion based on term co-occurrence data and suggests a way to maximize the retrieval effectiveness. Major parameters to be optimized through experiments are term similarity measure and the weighting scheme of additional terms. The evaluation of four similarity measures tested in query expansion reveal that mutual information and Yule's Y, which emphasize low frequency terms, achieve better performance than cosine and Jaccard coefficients that have the reverse tendency. In the evaluation of three weighting schemes, similarity weight performs well only with short queries, whereas fixed weights of approximately 0.5 and similarity rank weights were effective with queries of any length. Furthermore, the optimal similarity rank weight achieving the best overall performance seems to be the least affected by test collections and the number of additional terms. For the efficiency of retrieval, the number of additional terms needs not exceed 70 in our test collections, but the optimal number may vary according to the characteristics of the similarity measure employed.  相似文献   

Parsimonious translation models for information retrieval     

Seung-Hoon Na  In-Su KangJong-Hyeok Lee 《Information processing & management》2007

In the KL divergence framework, the extended language modeling approach has a critical problem of estimating a query model, which is the probabilistic model that encodes the user’s information need. For query expansion in initial retrieval, the translation model had been proposed to involve term co-occurrence statistics. However, the translation model was difficult to apply, because the term co-occurrence statistics must be constructed in the offline time. Especially in a large collection, constructing such a large matrix of term co-occurrences statistics prohibitively increases time and space complexity. In addition, reliable retrieval performance cannot be guaranteed because the translation model may comprise noisy non-topical terms in documents. To resolve these problems, this paper investigates an effective method to construct co-occurrence statistics and eliminate noisy terms by employing a parsimonious translation model. The parsimonious translation model is a compact version of a translation model that can reduce the number of terms containing non-zero probabilities by eliminating non-topical terms in documents. Through experimentation on seven different test collections, we show that the query model estimated from the parsimonious translation model significantly outperforms not only the baseline language modeling, but also the non-parsimonious models.  相似文献   

An empirical study of query expansion and cluster-based retrieval in language modeling approach     

Seung-Hoon Na  In-Su Kang  Ji-Eun Roh  Jong-Hyeok Lee 《Information processing & management》2007

The term mismatch problem in information retrieval is a critical problem, and several techniques have been developed, such as query expansion, cluster-based retrieval and dimensionality reduction to resolve this issue. Of these techniques, this paper performs an empirical study on query expansion and cluster-based retrieval. We examine the effect of using parsimony in query expansion and the effect of clustering algorithms in cluster-based retrieval. In addition, query expansion and cluster-based retrieval are compared, and their combinations are evaluated in terms of retrieval performance by performing experimentations on seven test collections of NTCIR and TREC.  相似文献   

Religious Development in African American Adolescents: Growth Patterns That Offer Protection     

Daniel B. Lee  Enrique W. Neblett 《Child development》2019,90(1):245-259

Although religiosity promotes resilient outcomes in African American (AA) adolescents, there is a lack of research that examines the protective role of religious development in the context of stressful life events (SLEs). In 1,595 AA adolescents, a cohort-sequential design was used from ages 12 to 18 to examine subtypes of religiosity, as well as distinct developmental patterns within subtypes. The protective role of religious development was also examined in the context of SLEs. The study findings indicated two subtypes of religiosity—extrinsic and intrinsic religiosity—as well as low and high developmental patterns in the identified subtypes. Furthermore, the protective influence of extrinsic and intrinsic religiosity gradually diminished from age 12 to 18 in the context of SLEs.  相似文献   

An Entity Theory of Intelligence Predicts Higher Cortisol Levels When High School Grades Are Declining     

Hae Yeon Lee  Jeremy P. Jamieson  Adriana S. Miu  Robert A. Josephs  David S. Yeager 《Child development》2019,90(6):e849-e867

Grades often decline during the high school transition, creating stress. The present research integrates the biopsychosocial model of challenge and threat with the implicit theories model to understand who shows maladaptive stress responses. A diary study measured declines in grades in the first few months of high school: salivary cortisol (N = 360 students, N = 3,045 observations) and daily stress appraisals (N = 499 students, N = 3,854 observations). Students who reported an entity theory of intelligence (i.e., the belief that intelligence is fixed) showed higher cortisol when grades were declining. Moreover, daily academic stressors showed a different lingering effect on the next day's cortisol for those with different implicit theories. Findings support a process model through which beliefs affect biological stress responses during difficult adolescent transitions.  相似文献   

Development as education for social justice     

Yoo  Sung-Sang  Mosrur  Ridwanul  Lee  Eunhye  Andrea  Diego Toca 《Asia Pacific Education Review》2019,20(2):259-272

Asia Pacific Education Review - The correlation between education and development, with time, went through many changes along with the changes of perspectives. Since both of these concepts...  相似文献   

Proposing an Effective Action Learning Process Model: Introducing the PAIR Model     

Yeol Huh  Dabae Lee 《Performance Improvement》2015,54(10):22-29

Action learning differentiates itself from other inquiry‐based learning approaches in that it requires learners to take actions based on project outcomes. While implementing their plans and reflecting on consequences of their actions, learners are given more and varied learning opportunities. Despite the apparent benefits of action learning, it entails a more complex process and a higher level of involvement from top management than do ordinary training programs. This article seeks to identify benefits and limitations of action learning and proposes a process model that enhances its benefits and helps to overcome its limitations. Thirty‐one research studies from academic journals were reviewed to identify espoused benefits and limitations of action learning. Those findings were used as the foundation for development of the PAIR model.  相似文献   

Multiple regression data using the WISC-R and the Woodcock-Johnson tests of cognitive ability     

Leadelle Phelps  Martin Rosso  Sharon Lee Falasco 《Psychology in the schools》1985,22(1):46-49

Using a sample of 100 behavior disordered male adolescents, correlations between the Wechsler Intelligence Scale for Children-Revised (WISC-R) and the Woodcock-Johnson Tests of Cognitive Abilities (WJTCA) were computed. All WISC-R subtests correlated with the W-J Broad Cognitive Ability score at the .0001 level. Analysis of the forward selection multiple regression procedure resulted in the inclusion of only WISC-R Verbal subtests for the first six steps. Implications of such results were discussed and a predictive equation reported.  相似文献   

The influence of lower limb amputation level on the approach in the amputee long jump     

Nolan L  Lees A 《Journal of sports sciences》2007,25(4):393-401

In this study, we investigated the adjustments to posture, kinematic and temporal characteristics of performance made by lower limb amputees during the last few strides in preparation for long jump take-off. Six male unilateral trans-femoral and seven male unilateral trans-tibial amputees competing in a World Championships final were filmed in the sagittal plane using a 100-Hz digital video camera positioned so that the last three strides to take-off were visible. After digitizing using a nine-segment model, a range of kinematic variables were computed to define technique characteristics. Both the trans-femoral and trans-tibial athletes appeared to achieve their reduction in centre of mass during the flight phase between strides, and did so mainly by extending the flight time by increasing stride length, achieved by a greater flexion of the hip joint of the touch-down leg. The trans-tibial athletes appeared to adopt a technique similar to that previously reported for able-bodied athletes. They lowered their centre of mass most on their second last stride (-1.6% of body height compared with -1.4% on the last stride) and used a flexed knee at take-off on the last stride, but they were less able to control their downward velocity at touch-down (-0.4 m x s(-1)). Both this and their restricted approach speed (8.9 m x s(-1) at touch-down), rather than technique limitations, influenced their jump performance. The trans-femoral athletes lowered their centre of mass most on the last stride (-2.3% of body height compared with -1.6% on the second last stride) and, as they were unable to flex their prosthetic knee sufficiently, achieved this by abducting their prosthetic leg during the support phase, which led to a large downward velocity at touch-down (-0.6 m x s(-1)). This, combined with their slower approach velocity (7.1 m x s(-1) at touch-down), restricted their performance.  相似文献   

Injectable hybrid inorganic nanoscaffold as rapid stem cell assembly template for cartilage repair     

Shenqiang Wang  Letao Yang  Bolei Cai  Fuwei Liu  Yannan Hou  Hua Zheng  Fang Cheng  Hepeng Zhang  Le Wang  Xiaoyi Wang  Qianxin Lv  Liang Kong  Ki-Bum Lee  Qiuyu Zhang 《国家科学评论(英文版)》2022,9(4)

Cartilage injuries are often devastating and most cannot be cured because of the intrinsically low regenerative capacity of cartilage tissues. Although stem-cell therapy has shown enormous potential for cartilage repair, the therapeutic outcome has been restricted by low survival rates and poor chondrocyte differentiation in vivo. Here, we report an injectable hybrid inorganic (IHI) nanoscaffold that facilitates fast assembly, enhances survival and regulates chondrogenic differentiation of stem cells. IHI nanoscaffolds that strongly bind to extracellular matrix (ECM) proteins assemble stem cells through synergistic 3D cell–cell and cell–matrix interactions, creating a favorable physical microenvironment for stem-cell survival and differentiation in vitro and in vivo. Additionally, chondrogenic factors can be loaded into nanoscaffolds with a high capacity, which allows deep, homogenous drug delivery into assembled 3D stem-cell-derived tissues for effective control over the soluble microenvironment of stem cells. The developed IHI nanoscaffolds that assemble with stem cells are injectable. They also scavenge reactive oxygen species and timely biodegrade for proper integration into injured cartilage tissues. Implantation of stem-cell-assembled IHI nanoscaffolds into injured cartilage results in accelerated tissue regeneration and functional recovery. By establishing our IHI nanoscaffold-templated 3D stem-cell assembly method, we provide a promising approach to better overcoming the inhibitory microenvironment associated with cartilage injuries and to advance current stem-cell-based tissue engineering.  相似文献