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This paper presents a generalized theoretical framework for carrier tracking of Global Navigation Satellite Systems signals by constructing a state space representation for the carrier tracking loop and applying control system design techniques to derive state feedback and state estimator gain matrices. Both phase locked loop and frequency locked loop are studied using this approach. Their performances are evaluated using the closed-form expressions in the presence of thermal noise, oscillator noise, and receiver platform dynamics. The proposed approach unified the phase tracking and frequency tracking within the same theoretical framework, thereby facilitating a systematic analysis of the effects of tracking loop design parameters under weak signal and highly dynamic signal environments.

This paper reports on a study of 35 Mandarin Chinese learners who (1) created pitch curves of their spoken word tones and (2) compared their pitch curves with those of native speakers while practicing pronunciation. Following a pretest, the learners received training for 20-25 minutes weekly over nine weeks and took a posttest. Two types of data analyses were performed. First, native speakers of Mandarin auditorily rated the pretests and posttests. The ratings revealed that learners' pronunciation of tones improved between pretest and posttest. Second, acoustic analyses of the learners' recordings were conducted, and the learners' production was compared with that of native speakers. Results indicated that students' pronunciation of some tones improved in the posttest. The postsurveys indicated that two-thirds of the participants found viewing pitch curves helpful. This study confirms previous research but suggests that acoustic analyses complement auditory analyses with more precise indications of L2 learners' tonal difficulties.

In this paper, the original Choquet integral is generalized as a Fuzzified Choquet Integral with a Fuzzy-valued Integrand (FCIFI), which supports a fuzzy-valued integrand and an integration result. The calculation of the FCIFI is established on the Choquet integral with an interval-valued integrand (CIII). The definitions, properties, and calculation algorithms of the CIII and the FCIFI are discussed and proposed in this paper. As a specific application scheme, we designed a CIII regression model for the regression problems involving interval-valued data. This CIII regression model has a self-learning ability through a double genetic algorithm. Finally, a daily temperature predictor based on the CIII regression model is discussed, where a series of experiments is implemented to validate the performance of the predictor by real weather records from the Hong Kong Observatory.