Technology survey and invalidity search: A comparative study of different tasks for Japanese patent document retrieval

A comparative study of two types of patent retrieval tasks, technology survey and invalidity search, using the NTCIR-3 and -4 test collections is described, with a focus on pseudo-feedback effectiveness and different retrieval models. Invalidity searches are peculiar to patent retrieval tasks and feature small numbers of relevant documents and long queries. Different behaviors of effectiveness are observed when applying different retrieval models and pseudo-feedback. These different behaviors are analyzed in terms of the “weak cluster hypothesis”, i.e., terminological cohesiveness through relevant documents.     

Effects of shocks,presented at a fixed time of day,on appetitive and general activity of rats

Eating, drinking, locomotion, and rearing activities of rats, maintained under a 12:12-h dark:light cycle, were measured continuously over 24 h a day for 40 days in the KGbox-24. For 20 days, beginning on Day 11, the shocks were given through the grid floor of the box 1 h after the beginning of the dark phase (at 2100 h). The daily food and water intake decreased, and there was no further gain in body weight after the introduction of shocks. The 2100-h shocks had some associative effects: (1) Suppression of ingestion developed during the period of 2000–2100 h; (2) acceleration of general activity developed during the period of 2000–2012 h; (3) anticipatory suppression of eating developed toward the end of the light phase. The 2100-h shocks also had suppressive aftereffects upon eating and drinking, especially during the early stage of the 20-day shock phase. Compensatory drinking was observed during the light phase, but no such effect was found for eating. Some findings which are not usually obtained in short-session experiments remain to be explained. References to two timing systems are made.     

Classical conditioning of an “avoidance” response in goldfish using a linear presentation procedure

The present study examined the nature of the “avoidance” response in goldfish under the linear presentation procedure (Zerbolio, 1981). With this procedure, shuttling behavior occurring during the presentation of the trial stimulus produces either CS? or CS+, and further occurrence of shuttling within the trial interval (10 sec) changes the value of CS from negative to positive, or vice versa. If the fish remains in the compartment when the prevailing cue state is CS? at the end of the interval, shock can be avoided. With this procedure fish responded to the CS+ more than to the CS? and avoided shock. But fish in one of two control groups, in which responses had no effect in changing the cue state from CS+ to CS?, or vice versa, also showed a clear differentiation. The results were generally in line with the view that the “avoidance” response in fish is acquired through classical conditioning. The contribution of classical conditioning to the acquisition of avoidance response is discussed.     

Retrieval parameter optimization using genetic algorithms

This paper describes our experiments on automatic parameter optimization for the Japanese monolingual retrieval task. Unlike regression approaches, we optimized parameters completely independently of retrieval models enabling the optimized parameter set to illustrate the characteristics of the target test collections. We adopted genetic algorithms as optimization tools and cross-validated with four test collections, namely the CLIR-J-J collections for NTCIR-3 to NTCIR-6. The most difficult retrieval parameters to optimize are the feedback parameters, because there are no principles for calibrating them. Our approach optimized feedback parameters and basic scoring parameters at the same time. Using test sets and validation sets, we achieved effectiveness levels comparable with very strong baselines, i.e., the best-performing NTCIR official runs.