45 research outputs found

    How Do Designers Deal With Uncertainty

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    Uncertainty touches most aspects of life and cannot be avoided, anybody is frequently presented with situations wherein a decision must be made when he/she is uncertain of exactly how to proceed. Narrow down into Information Systems (IS) field, uncertainty could be regarded as a basic but difficult problem that every HCI designer need to deal with within their design process. The purpose of this thesis is to find out how do human-computer interaction (HCI) practitioners deal with the uncertainty in their daily work. Based on this purpose, we assume that design approaches could be the methods for the designers to deal with uncertainty. There is however very few existing research on how to deal with uncertainty. In this study, we firstly categorized the uncertainty into a logical taxonomy, also ranked four design approaches by the extent of user involvement. We interviewed five HCI practitioners in different organizations that are or were working as designers. We found that most uncertainties are resulted from their customers, which can also be the most difficult to handle by them. In order to solve uncertainty, the designers need to make a good communication with others in specific situation, and some of them also proposed other practical solutions, such as “Role Play” and “Instinct Follower”. Additionally, the designers all proposed that the relationship between uncertainty and design approaches can be weak or inexistent. Interestingly, modest user involvement can be a helper for designers to solve or avoid uncertainty in the design process

    Development and validation of risk prediction model for identifying 30-day frailty in older inpatients with undernutrition: A multicenter cohort study

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    ObjectiveTo develop and externally validate a frailty prediction model integrating physical factors, psychological variables and routine laboratory test parameters to predict the 30-day frailty risk in older adults with undernutrition.MethodsBased on an ongoing survey of geriatrics syndrome in elder adults across China (SGSE), this prognostic study identified the putative prognostic indicators for predicting the 30-day frailty risk of older adults with undernutrition. Using multivariable logistic regression analysis with backward elimination, the predictive model was subjected to internal (bootstrap) and external validation, and its calibration was evaluated by the calibration slope and its C statistic discriminative ability. The model derivation and model validation cohorts were collected between October 2018 and February 2019 from a prospective, large-scale cohort study of hospitalized older adults in tertiary hospitals in China. The modeling derivation cohort data (n = 2,194) were based on the SGSE data comprising southwest Sichuan Province, northern Beijing municipality, northwest Qinghai Province, northeast Heilongjiang Province, and eastern Zhejiang Province, with SGSE data from Hubei Province used to externally validate the model (validation cohort, n = 648).ResultsThe incidence of frailty in the older undernutrition derivation cohort was 13.54% and 13.43% in the validation cohort. The final model developed to estimate the individual predicted risk of 30-day frailty was presented as a regression formula: predicted risk of 30-day frailty = [1/(1+e-riskscore )], where riskscore = -0.106 + 0.034 × age + 0.796 × sex -0.361 × vision dysfunction + 0.373 × hearing dysfunction + 0.408 × urination dysfunction - 0.012 × ADL + 0.064 × depression - 0.139 × nutritional status - 0.007 × hemoglobin - 0.034 × serum albumin - 0.012 × (male: ADL). Area under the curve (AUC) of 0.71 in the derivation cohort, and discrimination of the model were similar in both cohorts, with a C statistic of nearly 0.7, with excellent calibration of observed and predicted risks.ConclusionA new prediction model that quantifies the absolute risk of frailty of older patients suffering from undernutrition was developed and externally validated. Based on physical, psychological, and biological variables, the model provides an important assessment tool to provide different healthcare needs at different times for undernutrition frailty patients.Clinical trial registrationChinese Clinical Trial Registry [ChiCTR1800017682]

    Behavior Characteristics of Argon Bubbles on Inner Surface of Upper Tundish Nozzle during Argon Blowing Process

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    During continuous casting of aluminum-killed steel, clogging of tundish nozzle frequently occurs, which seriously disrupts the normal casting sequences and deteriorates strand quality. Generally, argon blowing technology in the form of a stable and continuous argon film on the inner surface of the upper nozzle is employed to prevent the upper nozzle from clogging in the production. To explore the formation mechanism and influence factors of this argon film, a water model of the upper nozzle with blowing argon with a similarity ratio of 1:1 was built. The results show that the number of bubble chains increases gradually with increasing argon flow rate and casting speed, and the argon gas curtain appears at the bottom half of the upper nozzle. For a given argon flow rate, the velocity of argon gas bubbles increased gradually with increasing casting speed, and decreased gradually with increasing distance from the upper nozzle top. For a given casting speed, the average velocity of argon gas bubbles was largest at a distance from the upper nozzle top of 6 mm with argon flow rate of 150 L/h. The results could provide theoretical and technical basis for the optimization of blowing argon parameters in order to prevent the clogging of upper nozzle and improve strand quality

    Delay Guaranteed Joint User Association and Channel Allocation for Fog Radio Access Networks

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    In the Fog Radio Access Networks (F-RANs), the local storage and computing capability of Fog Access Points (FAPs) provide new communication resources to address the latency and computing constraints for delay-sensitive applications. To achieve the ultra-low latency, a novel joint user association and channel allocation scheme is proposed in this paper, where the FAPs are clustered from a user-centric perspective. The delay performance is improved regarding both the control signaling procedure and the data transmission procedure. Specifically, the multiple access interference (MAI) between users is analyzed, where the closed-form expression for the effective rate of a typical user with multiple FAP connections and arbitrary interfering users is obtained. With the consideration of MAI, the proposed distributed joint user association and channel allocation algorithm provides a guaranteed delay violation probability. Moreover, the distributed algorithm can be conducted on individual FAPs, whose calculation is simplified by look-up tables. Simulation results show that the proposed algorithm is capable of providing statistical delay performance guarantee including both average delay and delay bound violation probability, which demonstrates its superiority in supporting delay-sensitive applications in FRANs

    A Method to Construct Depth Datum Geodesic Height Model for GNSS Bathymetric Survey

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    Water depth measurement requires the establishment of one or more tidal stations in the survey area for synchronous water level observation, and finally the water depth is estimated to the depth datum. The non-tidal observation measuring has high efficiency and avoids the water level correction error caused by tidal observation in traditional sounding. Therefore, non-tidal observation measuring has become an effective water depth measurement method in offshore and inland water. However, datum conversion in non-tide operation is mostly based on the polynomial fitting method. The accuracy of this method is influenced by the distribution of datum control points, topographic relief and operation ranges. In this paper, we present a method to construct a depth datum geodesic height model, which can directly obtain a bathymetric database of depth data in a GNSS bathymetric survey. The model incorporates the continuous depth datum and the mean sea level of geodetic height in the same area. Through the numerical simulation of tidal wave motion in regional water, the tidal model is obtained. Based on the grid model, the tidal level is extracted from the tidal model for harmonic analysis, and a continuous depth datum model is established. Mean sea level geodetic height is from the CNES-CLS2015 Average Sea Surface Model. In this paper, the model is confirmed in the South Yellow Sea area. The results show that the accuracy of the depth datum model, and the depth datum geodetic height model meets the accuracy requirements of the datum

    Theoretical Calculation and Analysis on the Composite Rock-Bolt Bearing Structure in Burst-Prone Ground

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    Given the increase in mining depth and intensity, tunnel failure as a result of rock burst has become an important issue in the field of mining engineering in China. Based on the Composite Rock-Bolt Bearing Structure, which is formed due to the interaction of the bolts driven into the surrounding rock, this paper analyzes a rock burst prevention mechanism, establishes a mechanical model in burst-prone ground, deduces the strength calculation formula of the Composite Rock-Bolt Bearing Structure in burst-prone ground, and confirms the rock burst prevention criterion of the Composite Rock-Bolt Bearing Structure. According to the rock burst prevention criterion, the amount of the influence on rock burst prevention ability from the surrounding rock parameters and bolt support parameters is discussed

    Morphological Analysis of a Collapsing Cavitation Bubble near a Solid Wall with Complex Geometry

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    The interaction mechanism between the cavitation bubble and a solid wall is a basic problem in bubble collapse prevention and application. In particular, when bubble collapse occurs near solid walls with arbitrarily complex geometries, it is difficult to efficiently establish a model and quantitatively explore the interaction mechanism between bubbles and solid walls. Based on the advantages of the lattice Boltzmann method, a model for cavitation bubble collapse close to a solid wall was established using the pseudopotential multi-relaxation-time lattice Boltzmann model. Solid walls with arbitrarily complex geometries were introduced in the computational domain, and the fractal dimension was used to quantify the complexity of the solid wall. Furthermore, owing to the lack of periodicity, symmetry, spatial uniformity and obvious correlation in this process, the Minkowski functionals-based morphological analysis method was introduced to quantitatively describe the temporal evolution of collapsing bubble profiles and acquire effective information from the process. The interaction mechanism between the bubble and solid wall was investigated using evolutions of physical fields. In addition, the influences of the solid walls’ surface conditions and the position parameter on collapsing bubbles were discussed. These achievements provide an efficient tool for quantifying the morphological changes of the collapsing bubble

    Morphological Analysis of a Collapsing Cavitation Bubble near a Solid Wall with Complex Geometry

    No full text
    The interaction mechanism between the cavitation bubble and a solid wall is a basic problem in bubble collapse prevention and application. In particular, when bubble collapse occurs near solid walls with arbitrarily complex geometries, it is difficult to efficiently establish a model and quantitatively explore the interaction mechanism between bubbles and solid walls. Based on the advantages of the lattice Boltzmann method, a model for cavitation bubble collapse close to a solid wall was established using the pseudopotential multi-relaxation-time lattice Boltzmann model. Solid walls with arbitrarily complex geometries were introduced in the computational domain, and the fractal dimension was used to quantify the complexity of the solid wall. Furthermore, owing to the lack of periodicity, symmetry, spatial uniformity and obvious correlation in this process, the Minkowski functionals-based morphological analysis method was introduced to quantitatively describe the temporal evolution of collapsing bubble profiles and acquire effective information from the process. The interaction mechanism between the bubble and solid wall was investigated using evolutions of physical fields. In addition, the influences of the solid walls’ surface conditions and the position parameter on collapsing bubbles were discussed. These achievements provide an efficient tool for quantifying the morphological changes of the collapsing bubble
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