357 research outputs found
On Reliability of Underwater Magnetic Induction Communications with Tri-Axis Coils
Underwater magnetic induction communications (UWMICs) provide a low-power and
high-throughput solution for autonomous underwater vehicles (AUVs), which are
envisioned to explore and monitor the underwater environment. UWMIC with
tri-axis coils increases the reliability of the wireless channel by exploring
the coil orientation diversity. However, the UWMIC channel is different from
typical fading channels and the mutual inductance information (MII) is not
always available. It is not clear the performance of the tri-axis coil MIMO
without MII. Also, its performances with multiple users have not been
investigated. In this paper, we analyze the reliability and multiplexing gain
of UWMICs with tri-axis coils by using coil selection. We optimally select the
transmit and receive coils to reduce the computation complexity and power
consumption and explore the diversity for multiple users. We find that without
using all the coils and MII, we can still achieve reliability. Also, the
multiplexing gain of UWMIC without MII is 5dB smaller than typical terrestrial
fading channels. The results of this paper provide a more power-efficient way
to use UWMICs with tri-axis coils
Efficient Subgraph Matching on Billion Node Graphs
The ability to handle large scale graph data is crucial to an increasing
number of applications. Much work has been dedicated to supporting basic graph
operations such as subgraph matching, reachability, regular expression
matching, etc. In many cases, graph indices are employed to speed up query
processing. Typically, most indices require either super-linear indexing time
or super-linear indexing space. Unfortunately, for very large graphs,
super-linear approaches are almost always infeasible. In this paper, we study
the problem of subgraph matching on billion-node graphs. We present a novel
algorithm that supports efficient subgraph matching for graphs deployed on a
distributed memory store. Instead of relying on super-linear indices, we use
efficient graph exploration and massive parallel computing for query
processing. Our experimental results demonstrate the feasibility of performing
subgraph matching on web-scale graph data.Comment: VLDB201
Unraveling the "Anomaly" in Time Series Anomaly Detection: A Self-supervised Tri-domain Solution
The ongoing challenges in time series anomaly detection (TSAD), notably the
scarcity of anomaly labels and the variability in anomaly lengths and shapes,
have led to the need for a more efficient solution. As limited anomaly labels
hinder traditional supervised models in TSAD, various SOTA deep learning
techniques, such as self-supervised learning, have been introduced to tackle
this issue. However, they encounter difficulties handling variations in anomaly
lengths and shapes, limiting their adaptability to diverse anomalies.
Additionally, many benchmark datasets suffer from the problem of having
explicit anomalies that even random functions can detect. This problem is
exacerbated by ill-posed evaluation metrics, known as point adjustment (PA),
which can result in inflated model performance. In this context, we propose a
novel self-supervised learning based Tri-domain Anomaly Detector (TriAD), which
addresses these challenges by modeling features across three data domains -
temporal, frequency, and residual domains - without relying on anomaly labels.
Unlike traditional contrastive learning methods, TriAD employs both
inter-domain and intra-domain contrastive loss to learn common attributes among
normal data and differentiate them from anomalies. Additionally, our approach
can detect anomalies of varying lengths by integrating with a discord discovery
algorithm. It is worth noting that this study is the first to reevaluate the
deep learning potential in TSAD, utilizing both rigorously designed datasets
(i.e., UCR Archive) and evaluation metrics (i.e., PA%K and affiliation).
Through experimental results on the UCR dataset, TriAD achieves an impressive
three-fold increase in PA%K based F1 scores over SOTA deep learning models, and
50% increase of accuracy as compared to SOTA discord discovery algorithms.Comment: This work is submitted to IEEE International Conference on Data
Engineering (ICDE) 202
Rational selection of small molecules that increase transcription through the GAA repeats found in Friedreich’s ataxia
AbstractFriedreich’s ataxia (FRDA) is an autosomal recessive trinucleotide repeat disease with no effective therapy. Expanded GAA repeats in the first intron of the FRDA gene are thought to form unusual non-B DNA conformations that decrease transcription and subsequently reduce levels of the encoded protein, frataxin. Frataxin plays a crucial role in iron metabolism and detoxification. To discover small molecules that increase transcription through the GAA repeat region in FRDA, we have made stable cell lines containing a portion of expanded intron 1 fused to a GFP reporter. Small molecules identified using the competition dialysis method were found to increase FRDA-intron 1-reporter gene expression. One of these compounds, pentamidine, increases frataxin levels in patient cells. Thus our approach can be used to detect small molecules of potential therapeutic value in FRDA
Novel Refrigeration Cycle with Continuous Cooling Turbo Compressor and Condensing Ejector Using Water as Refrigerant
Turbo chiller using water as a refrigerant was developed. A refrigeration cycle using water (R718) as a refrigerant has a high theoretical efficiency, but the cycle pressure ratio is high, and the compressor discharge temperature is elevated. Although the conversion of the compressor to a multistage compressor and the addition of an intercooler between each stage are known to lower the discharge temperature and improve performance, the resulting increased size is problematic. To resolve this issue, this study develops a refrigeration cycle that lowers discharge temperature during the compression process without enlarging the device. Using a continuous cooling compressor that compresses refrigerant vapor while continuously cooling it in process and a condensing ejector that condenses the vapor while compressing it, we experimentally verify the performance of each element. Based on the results, we verify the basic principles of a continuous cooling compressor for continuously cooling compressed vapor with refrigerant droplets sprayed by nozzles installed on the impeller. In addition, the condensing ejector uses a high-speed fine refrigerant droplets to transfer momentum to the refrigerant vapor. And thus raises its pressure within a two-phase state and simultaneously condensing refrigerant vapor
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