2,216 research outputs found

    Consistent testing for lag length in cointegrated relationships

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    In the past few decades the theory of cointegration has been widely used in the empirical analysis of economic data. The reason is that, it captures the economic notion of a long-run economic relation. One of the problems experienced when applying cointegrated techniques to econometric modelling is the determination of lag lengths for the modelled variables. Applied studies have resulted in contradictory choices for lag length selection. This study reviews and compares some of the well-known information criteria using simulation techniques for bivariate models

    Marked causative structures of Chinese verb-resultative construction

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    This paper aims to study the syntactic and semantic features of ‘marked VRC causative structures’, those special syntactic-semantic structures formed by verb-resultative constructions (VRCs) which violate both the Uniformity of Theta Assignment Hypothesis and the Thematic Hierarchy. Their syntactic and semantic features are defined as follows: 1) VRC has a causative relation within itself; 2) the argument in the object position is the causee and the only argument of the resultative complement; 3) the causer in the subject position is any conceptual component from the cause event other than the agent of the predicate verb. This paper then attempts to propose an extended account to expound how they are formed syntactically and semantically. On this account, a marked VRC causative structure is re-causativization of a VRC when the VRC is self-causative; it enables other conceptual components of the cause event than the agent to become the causer when a VRC is not self-causative. There are some constraints on what becomes the causer of a marked VRC causative structure

    Gongsun Longzi’s “form”: Minimal word meaning

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    Inspired by Gongsun Longzi’s “form-naming” idea about word meaning, this paper argues that 1) the internal lexicon contains only the list of word-meaning pairs, with no additional information either as part of word meaning or as a structural level above it; 2) the meaning of word is a minimal C-Form, the identifying conceptual meaning that individuates a concept; 3) C-Form is the interface between word meaning and concept meaning; and 4) a sentence has a minimal semantic content, consisting of the minimal meanings of the words composing it, which is propositional and truth-evaluable, and contextual elements contribute nothing to the meaning of language expressions. This paper adheres to semantic minimalism, believing meanwhile that meaning holism helps in semantics inquiry, since reflection on language meaning differs from language meaning itself. 

    A High-Accuracy Nonintrusive Networking Testbed for Wireless Sensor Networks

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    It becomes increasingly important to obtain the accurate and spontaneous runtime network behavior for further studies onwireless sensor networks. However, the existing testbeds cannot appropriately match such requirements. A High-accuracyNonintrusive Networking Testbed (HINT) is proposed. In HINT, the interconnected chip-level signals are passively captured withauxiliary test boards and the captured data are transferred in additional networks to test server. The test server of HINT collects allthe test data and depicts the full network behavior. HINT supports networking test, protocol verification, performance evaluationand so on. The experiments show that HINT transparently gathers accurate runtime data and does not disturb the spontaneousbehavior of sensor networks. HINT is also extendible to different hardware platforms of sensor nodes. Consequently, HINT isan upstanding testbed solution for the future fine-grained and experimental studies on the resource-constrained wireless sensornetworks

    Ambient Data Collection with Wireless Sensor Networks

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    One of the most important applications for wireless sensor networks (WSNs) is Data Collection, where sensing data arecollected at sensor nodes and forwarded to a central base station for further processing. Since using battery powers and wirelesscommunications, sensor nodes can be very small and easily attached at specified locations without disturbing surroundingenvironments. This makes WSN a competitive approach for data collection comparing with its wired counterpart. In this paper,we review recent advances in this research area. We first highlight the special features of data collection WSNs, by comparingwith wired data collection network and other WSN applications. With these features in mind, we then discuss issues and priorsolutions on the data gathering protocol design. Our discussion also covers different approaches for message dissemination, whichis a critical component for network control and management and greatly affects the overall performance of a data collectionWSNsystem

    Pituitary Morphology and Function in 43 Children with Central Diabetes Insipidus

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    Objective. In pediatric central diabetes insipidus (CDI), etiology diagnosis and pituitary function monitoring are usually delayed. This study aimed to illustrate the importance of regular follow-up and pituitary function monitoring in pediatric CDI. Methods. The clinical, hormonal, and neuroradiological characteristics of children with CDI at diagnosis and during 1.5–2-year follow-up were collected and analyzed. Results. The study included 43 CDI patients. The mean interval between initial manifestation and diagnosis was 22.29 ± 3.67 months (range: 2–108 months). The most common complaint was polyuria/polydipsia. Causes included Langerhans cell histiocytosis, germinoma, and craniopharyngioma in 2, 5, and 4 patients; the remaining were idiopathic. No significant changes were found during the 1.5–2 years after CDI diagnosis. Twenty-three of the 43 cases (53.5%) had ≥1 anterior pituitary hormone deficiency. Isolated growth hormone deficiency was the most frequent abnormality (37.5%) and was not associated with pituitary stalk diameter. Multiple pituitary hormone deficiencies were found in 8 cases with pituitary stalk diameter > 4.5 mm. Conclusion. Diagnosis of CDI is usually delayed. CDI with a pituitary stalk diameter > 4.5 mm carries a higher risk of multiple pituitary hormone deficiencies. Long-term MRI and pituitary function follow-ups are necessary for children with idiopathic CDI

    Photoconductivity of Single-crystalline Selenium Nanotubes

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    Photoconductivity of single-crystalline selenium nanotubes (SCSNT) under a range of illumination intensities of a 633nm laser is carried out with a novel two terminal device arrangement at room temperature. It's found that SCSNT forms Schottky barriers with the W and Au contacts, and the barrier height is a function of the light intensities. In low illumination regime below 1.46x10E-4 muWmum-2, the Au-Se-W hybrid structure exhibits sharp switch on/off behavior, and the turn-on voltages decrease with increasing illuminating intensities. In the high illumination regime above 7x10E-4 muWmum-2, the device exhibits ohmic conductance with a photoconductivity as high as 0.59Ohmcm-1, significantly higher that reported values for carbon and GaN nanotubes. This finding suggests that SCSNT is potentially a good photo-sensor material as well we a very effective solar cell material.Comment: 12pages including 5 figures, submitted to Nanotechnolog