Spectral Analysis for Semantic Segmentation with Applications on Feature Truncation and Weak Annotation

We propose spectral analysis to investigate the correlation between the accuracy and the resolution of segmentation maps for semantic segmentation. The current networks predict segmentation maps on the down-sampled grid of images to alleviate the computational cost. Moreover, these networks can be trained by weak annotations that utilize only the coarse contour of segmentation maps. Despite the successful achievement of these works utilizing the low-frequency information of segmentation maps, however, the accuracy of resultant segmentation maps may also be degraded in the regions near object boundaries. It is yet unclear for a theoretical guideline to determine an optimal down-sampled grid to strike the balance between the cost and the accuracy of segmentation. We analyze the objective function (cross-entropy) and network back-propagation process in frequency domain. We discover that cross-entropy and key features of CNN are mainly contributed by the low-frequency components of segmentation maps. This further provides us quantitative results to determine the efficacy of down-sampled grid of segmentation maps. The analysis is then validated on the two applications: the feature truncation method and the block-wise annotation that limit the high-frequency components of the CNN features and annotation, respectively. The results agree with our analysis. Thus the success of the existing work utilizing low-frequency information of segmentation maps now has theoretical foundation.Comment: 21 page

Perceived Athletic and Academic Stressors and Time Management of Student-Athletes

A typical National Collegiate Athletic Association (NCAA) Division-I affiliated member institution provides support to at least seven men’s and women’s sports that sustains over 300 student-athletes. These student-athletes perform both on and off the court on a daily basis while completing their homework and studying for tests just like non-athlete students. Furthermore, they participate in practices, compete in games, lift weights, attend team meetings, and manage injuries. Although faculty members are aware of the demands placed on college athletes, it’s unclear if they understand the magnitude of the challenges and pressure college athletes have experienced outside of the classroom

THE BIOMECHANICAL ANALYSIS OF ROUNDHOUSE KICK IN TAEKWONDO

The purpose of this research was to compare 360° turning roundhouse kick performed by dominant leg and non-dominant leg on kinetic and kinematic variables, and then to find the variables that correlate to the impact velocity. Nine elite taekwondo athletes were recruited. The data were collected with two Redlake cameras (125 Hz) and two Kistler force plates (1250 Hz). The difference between maximal height and beginning of body CM, max velocity of toe/ankle, impact velocity of toe, maximal vertical force of front leg, vertical/horizontal impulse of front leg, were found to be significantly different between dominant and non-dominant leg; and the difference between maximal height and impact of body CM, max velocity of toe/ankle, maximal vertical force of back leg were found to be significantly correlated with the impact velocity

The Association between Virus Prevalence and Intercolonial Aggression Levels in the Yellow Crazy Ant, Anoplolepis Gracilipes (Jerdon).

The recent discovery of multiple viruses in ants, along with the widespread infection of their hosts across geographic ranges, provides an excellent opportunity to test whether viral prevalence in the field is associated with the complexity of social interactions in the ant population. In this study, we examined whether the association exists between the field prevalence of a virus and the intercolonial aggression of its ant host, using the yellow crazy ant (Anoplolepis gracilipes) and its natural viral pathogen (TR44839 virus) as a model system. We delimitated the colony boundary and composition of A. gracilipes in a total of 12 study sites in Japan (Okinawa), Taiwan, and Malaysia (Penang), through intercolonial aggression assay. The spatial distribution and prevalence level of the virus was then mapped for each site. The virus occurred at a high prevalence in the surveyed colonies of Okinawa and Taiwan (100% infection rate across all sites), whereas virus prevalence was variable (30%-100%) or none (0%) at the sites in Penang. Coincidentally, colonies in Okinawa and Taiwan displayed a weak intercolonial boundary, as aggression between colonies is generally low or moderate. Contrastingly, sites in Penang were found to harbor a high proportion of mutually aggressive colonies, a pattern potentially indicative of complex colony composition. Our statistical analyses further confirmed the observed correlation, implying that intercolonial interactions likely contribute as one of the effective facilitators of/barriers to virus prevalence in the field population of this ant species

The Information-Leveling Role of Voluntary Disclosure Quality in Facilitating Investment Efficiency

This study examines whether and under what conditions voluntary disclosure quality plays an information-leveling role in facilitating investment efficiency. Measuring voluntary disclosure quality as the (inverse) standard deviation of managers’ prior earnings forecast errors (i.e., management forecast consistency), we document a positive association between management forecast consistency and investment efficiency that strengthens when the information environment becomes more constrained and when there are negative shocks to financial reporting quality. We also find that the management forecast consistency/investment efficiency association strengthens when firms are younger, faster growing, and financially constrained, but not when firms are weakly governed and financially unconstrained, which suggests that voluntary disclosure quality facilitates investment efficiency by mitigating adverse selection (but not moral hazard) frictions. Last, when we employ a changes-based model, we find that increases in management forecast consistency are associated with increases in investment efficiency, which mitigates concerns that voluntary disclosure quality’s empirical link to investment efficiency is purely driven by managers’ inherent forecasting abilities. Overall, we show that voluntary disclosure quality can facilitate investment efficiency when financial reporting and other elements of the information environment are constrained in their ability to mitigate market frictions that impede efficiency

Calculation of Weighted Geometric Dilution of Precision

To achieve high accuracy in wireless positioning systems, both accurate measurements and good geometric relationship between the mobile device and the measurement units are required. Geometric dilution of precision (GDOP) is widely used as a criterion for selecting measurement units, since it represents the geometric effect on the relationship between measurement error and positioning determination error. In the calculation of GDOP value, the maximum volume method does not necessarily guarantee the selection of the optimal four measurement units with minimum GDOP. The conventional matrix inversion method for GDOP calculation demands a large amount of operation and causes high power consumption. To select the subset of the most appropriate location measurement units which give the minimum positioning error, we need to consider not only the GDOP effect but also the error statistics property. In this paper, we employ the weighted GDOP (WGDOP), instead of GDOP, to select measurement units so as to improve the accuracy of location. The handheld global positioning system (GPS) devices and mobile phones with GPS chips can merely provide limited calculation ability and power capacity. Therefore, it is very imperative to obtain WGDOP accurately and efficiently. This paper proposed two formations of WGDOP with less computation when four measurements are available for location purposes. The proposed formulae can reduce the computational complexity required for computing the matrix inversion. The simpler WGDOP formulae for both the 2D and the 3D location estimation, without inverting a matrix, can be applied not only to GPS but also to wireless sensor networks (WSN) and cellular communication systems. Furthermore, the proposed formulae are able to provide precise solution of WGDOP calculation without incurring any approximation error

Masking Improves Contrastive Self-Supervised Learning for ConvNets, and Saliency Tells You Where

While image data starts to enjoy the simple-but-effective self-supervised learning scheme built upon masking and self-reconstruction objective thanks to the introduction of tokenization procedure and vision transformer backbone, convolutional neural networks as another important and widely-adopted architecture for image data, though having contrastive-learning techniques to drive the self-supervised learning, still face the difficulty of leveraging such straightforward and general masking operation to benefit their learning process significantly. In this work, we aim to alleviate the burden of including masking operation into the contrastive-learning framework for convolutional neural networks as an extra augmentation method. In addition to the additive but unwanted edges (between masked and unmasked regions) as well as other adverse effects caused by the masking operations for ConvNets, which have been discussed by prior works, we particularly identify the potential problem where for one view in a contrastive sample-pair the randomly-sampled masking regions could be overly concentrated on important/salient objects thus resulting in misleading contrastiveness to the other view. To this end, we propose to explicitly take the saliency constraint into consideration in which the masked regions are more evenly distributed among the foreground and background for realizing the masking-based augmentation. Moreover, we introduce hard negative samples by masking larger regions of salient patches in an input image. Extensive experiments conducted on various datasets, contrastive learning mechanisms, and downstream tasks well verify the efficacy as well as the superior performance of our proposed method with respect to several state-of-the-art baselines

Small noncoding RNA modulates japanese encephalitis virus replication and translation in trans

<p>Abstract</p> <p>Background</p> <p>Sequence and structural elements in the 3'-untranslated region (UTR) of Japanese encephalitis virus (JEV) are known to regulate translation and replication. We previously reported an abundant accumulation of small subgenomic flaviviral RNA (sfRNA) which is collinear with the highly conserved regions of the 3'-UTR in JEV-infected cells. However, function of the sfRNA in JEV life cycle remains unknown.</p> <p>Results</p> <p>Northern blot and real-time RT-PCR analyses indicated that the sfRNA becomes apparent at the time point at which minus-strand RNA (antigenome) reaches a plateau suggesting a role for sfRNA in the regulation of antigenome synthesis. Transfection of minus-sense sfRNA into JEV-infected cells, in order to counter the effects of plus-sense sfRNA, resulted in higher levels of antigenome suggesting that the presence of the sfRNA inhibits antigenome synthesis. <it>Trans</it>-acting effect of sfRNA on JEV translation was studied using a reporter mRNA containing the luciferase gene fused to partial coding regions of JEV and flanked by the respective JEV UTRs. <it>In vivo </it>and <it>in vitro </it>translation revealed that sfRNA inhibited JEV translation.</p> <p>Conclusions</p> <p>Our results indicate that sfRNA modulates viral translation and replication <it>in trans</it>.</p