Anti-jamming Wireless Sensor Network Model

A wireless sensor network (WSN) of a tree-like topology is considered, which performs measurements and transmits their results to the consumer. Under the interference influence, the WSN nodes transmitters low power makes the transmitted information vulnerable, which leads to significant data loss. To reduce the data loss during transmission, a noise-immune WSN model is proposed. Such a WSN, having detected a stable connection absence between a pair of nodes, transfers the interaction between these nodes to a radio channel free from interference influence. For this, the model, in addition to forming a network and transferring application data, provides for checking the communication availability based on the keep-alive mechanism and restoring the network with a possible channel change. A feature point of the proposed approach is the ability to restore network connectivity when exposed to interference of significant power and duration, which makes it impossible to exchange service messages on the channel selected for the interaction of nodes. To support the model, work algorithms and data structures have been developed, indicators have been formalized to assess an anti-jamming system work quality.

Minimizing Zapping Delay Using Adaptive Channel Switching with Personalized Electronic Program Guide

The pervasive acceptability of a revolution from monodirectional push-based media broadcasting to a bidirectional interactive pull-based internet protocol television (IPTV) has spotted significant development in recent years. The pervasive acceptability is because of the mammoth number of exhilarating television (TV) channels that IPTV offers. However, the channel switching feature of a TV system requires additional development despite the increased implementation of IPTV systems worldwide. Subscribers of IPTV services must be able to swiftly explore live TV stations and video contents of interest seamlessly, but zapping delay is a deterrent that occurs during a channel change that causes a significant glitch in IPTV systems. Many of the literature approaches such as channel prediction based on behavior analysis have shown flaws in resolving zapping delay. The approach of this study uses adaptive channel switching with a personalized electronic program guide to resolving zapping delay. The resolution saves the subscribers the time of channel navigation by eliminating the need to search for channels they want to view.

Analysis of Starbucks Supply Chain Status Based on 3A3S Model

The 3A supply chain was proposed by Stanford University Professor Hau L. Lee in 2004. In the past five years, he has studied more than 60 leading companies focusing on supply chain management, including Wal Mart, best buy and Martha, and found that the first-class supply chain has three characteristics: agility, alignment, and adaptation. It represents the best state of current supply chain management. He believes that only enterprises with the 3A supply chain can continue to gain a competitive advantage and take the lead in the competition. 3S model refers to the analysis of substitution effect (business substitution), scale effect (scale expansion) and structure effect (production structure and distribution channel change) used in enterprise supply chain management. This paper aims to use the 3A3S model to analyze the current situation of the company’s supply chain with Starbucks as an example and draw conclusions through detailed research and analysis, to provide some experience and lessons for more enterprises’ supply chain management.

The Signal of Modern to Holocene Drivers of Complex Channel Response of a Small Alluvial Stream

Small alluvial streams (~100km2 drainage area) are important for water resources and aquatic habitat. Small streams throughout the Western United States are impacted by anthropogenic land-use including urban development, mining, logging, beaver trapping, grazing, and farming. Land-use change can trigger a complex series of channel response (such as stream channel incision or channel migration) that vary spatially and temporally in the watershed. However, streams also respond to other external forcings, such as tectonically or climatically-driven changes in discharge or base-level, which make disentangling the drivers of channel response complicated. Therefore, it is important to place modern channel changes into a longer geomorphic context to fully understand the complex response initiated by land-use. In order to understand how changes in land-use may drive spatially variable channel response, we examine a representative small alluvial stream, Lower Dry Creek (LDC), a tributary to the Boise River in Idaho. LDC marks the transition from the rugged and largely undeveloped upland Dry Creek Experimental Watershed to the lower gradient, agricultural, and residential section of the watershed. LDC has a complex history of placer mining, beaver trapping, grazing, and farming since the 1850's. Recent (post-1997) growth in the region converted LDC's expansive floodplain from agricultural land to housing developments. Most of the recent development and historic and current farmland are on the broad, low gradient Hidden Springs Terrace. We use remote sensing, hydraulic modeling, grain size analysis, and field observations to quantify how the distinct reaches of LDC are changing over human time scales; we use Quaternary dating methods and geomorphic mapping to examine how LDC has changed over centennial to millennial time scales. Optically Stimulated Luminescence (OSL) dates of fluvial sediments in an upper reach indicate incision in LDC after 4.79 ± 1.05 ka. Around 0.79 to 0.67 ka, LDC deposited a large packet of sheetfloods and cross-bedded sands, which correlate to a period of more fire activity and alluvial fan deposition in the region. After approximately 0.67 ka the reach incised 2.4 m. In the late 1800's, placer mining in the upper reach of LDC shifted the channel behavior from incision to lateral adjustment. We measured an average of 0.6 m/yr of meander migration from 1938 to 2019. Migration rate increased threefold after 1992 (which corresponds temporally with a large rain-on-snow flood event in 1997), but slowed after 2011. Comparison of the modern longitudinal profile of LDC with the longitudinal profile of the Hidden Springs Terrace, combined with grain size analysis and historic dating reveals the impact of prior land use change on the present channel. LDC's current profile is convex in middle reaches, and grain size analysis shows a fining in the middle reaches and then coarsening downstream. The convexity and grain size change is consistent with increased aggradation from a slug of sediment from upstream placer mining progressing downstream. Downstream where the valley is unconfined, LDC aggraded 0.75 cm/yr from 1642 to 1950 AD to form the broad Hidden Springs Terrace. Notably, a lower reach of LDC has recently and profoundly incised, affecting local landowners and cutting off access of the stream to its floodplain. This downstream reach is incised 4.7 m below the Hidden Springs Terrace; a modern radiocarbon date provides evidence the incision happened post-1950 AD, potentially from channelization of Currant Creek (a tributary of LDC) as farmland is converted to housing. Hydraulic modeling shows LDC's median grain size is mobile at estimated bankfull flows for all reaches, which allows the stream to rapidly adjust both vertically and laterally. LDC channel response in the upper and lower reaches indicates anthropogenic land-use resulted in vertical and lateral channel change: upstream aggradation and meander migration following placer mining, and downstream incision following farmland conversion. This represents a shift from the observed channel adjustments and large-scale formation of the Hidden Springs Terrace observed over Holocene timescales. LDC illustrates textbook "complex response" as the stream both incises and aggrades in different locations due to differing drivers. This study shows small alluvial streams can be very sensitive to changes in land-use. Stream incision, aggradation, and channel shifts impact aquatic and riparian species and developments adjacent to the channel. This study illustrates the importance of examining the drivers of modern channel change within a longer more complete context. Results of this study can support stakeholders as they strive to understand the characteristics and response of small alluvial streams to anthropogenic land-use, and best options for restoration of degraded systems.

Collision Minimization Beacon Scheduling Scheme using RPL in Dense TSCH-based IoT Environment

IEEE 802.15.4e Time Slotted Channel Hopping (TSCH) operates on a time-division scheme and uses 16 separate channels for each communication to ensure high reliability even in an industrial environment where many devices are concentrated. The process of participating in the network is indispensable because the entire network operates at the same time. However, there is a problem with TSCH's channel change technique, which results in longer network participation time for new nodes wanting to participate in the network. Previous research has randomly chosen channels for beaconing to reduce network formation time. However, this approach is effective for networks with fewer nodes, but conflicts in beacon messages in networks with approximately 20 or more networks result in network congestion, which increases network participation time. To solve this problem, this paper proposes a collision minimization scheduling technique. This strategy assigns a separate time zone to each node to exclude the possibility of beacon message collisions. This algorithm allocates timeslot based on RANK of RPL. By explicitly predicting the longest network joining time of the network participating nodes, the average network joining time was measured to be about 25 seconds to 27 seconds faster compared to the previous research.