Fixed Time Slot Research Articles

Automated Density Based Traffic Light Control System Using Arduino Platform

In recent years, traffic Jams has become a serious problem across the globe. Current statistics reveals that, an average person spends around 4-6 months of his/her life by simply waiting for green light during traffic. Also when delay increases, it affects the commuters reach their destination so late resulting in severe consequences on day and day basis. In common, traffic can be controlled in several main junctions by incorporating either automated traffic light control system or through manual intervention by traffic police. However conventional traffic light system which involves fixed time slot allotted to each side of the junction is found to be poor efficient since it does not consider the varying traffic density. At certain instances, priority of the traffic system has to be changed dynamically based on more number of vehicles waiting on the road, arrival of VIP vehicles and ambulance vehicles etc. By considering the above facts, we have proposed an automated traffic light system which has inbuilt potential to prioritize the lane which is heavily congested. Our proposed system includes timer which runs for a specific time period and IR sensor is used to count the number of vehicles passing by during that time period. It also includes LED which is turned green on the lane with more number of vehicles. These peripherals were actuated based on the programming logic that is embedded in Arduino Mega platform. Finally, implementation results for the proposed system are provided in this paper.

Improved MAC layer protocol of Wifi for satellite network.

With the development and universal application of satellite technology, an important way to expand the function of satellites is setting up inter-satellite networks to make them work together. Traditional satellite networking methods generally adopt a fixed time slot allocation method, which is not suitable for small satellite groups with low latency and high throughput requirements. In order to solve this problem, it has been proposed to apply the traditional Wifi protocol in satellite networking. As there are differences between satellite networks and terrestrial networks, it’s necessary to improve the traditional 802.11 protocol. The Media Access Control (MAC) protocol in 802.11 is improved in this paper, which mainly includes the adaptive algorithm of maximum contention window size and the growth algorithm of Contention Window (CW) size. The maximum contention window is adjusted according to the conflict state of the current network, which makes the network accommodate more satellite nodes. The CW growth algorithm improves the traditional Binary Exponential Back-off (BEB) algorithm, where the CW is designed according to the priority of the data frame or the network load. In this way, high-priority satellite accusation information will have higher reliability or tolerate greater network load.

Asynchronous non-invasive high-speed BCI speller with robust non-control state detection

Brain-Computer Interfaces (BCIs) enable users to control a computer by using pure brain activity. Recent BCIs based on visual evoked potentials (VEPs) have shown to be suitable for high-speed communication. However, all recent high-speed BCIs are synchronous, which means that the system works with fixed time slots so that the user is not able to select a command at his own convenience, which poses a problem in real-world applications. In this paper, we present the first asynchronous high-speed BCI with robust distinction between intentional control (IC) and non-control (NC), with a nearly perfect NC state detection of only 0.075 erroneous classifications per minute. The resulting asynchronous speller achieved an average information transfer rate (ITR) of 122.7 bit/min using a 32 target matrix-keyboard. Since the method is based on random stimulation patterns it allows to use an arbitrary number of targets for any application purpose, which was shown by using an 55 target German QWERTZ-keyboard layout which allowed the participants to write an average of 16.1 (up to 30.7) correct case-sensitive letters per minute. As the presented system is the first asynchronous high-speed BCI speller with a robust non-control state detection, it is an important step for moving BCI applications out of the lab and into real-life.

Fuzzy-Based Dynamic Time Slot Allocation forWireless Body Area Networks.

With the advancement in networking, information and communication technologies, wireless body area networks (WBANs) are becoming more popular in the field of medical and non-medical applications. Real-time patient monitoring applications generate periodic data in a short time period. In the case of life-critical applications, the data may be bursty. Hence the system needs a reliable energy efficient communication technique which has a limited delay. In such cases the fixed time slot assignment in medium access control standards results in low system performance. This paper deals with a dynamic time slot allocation scheme in a fog-assisted network for a real-time remote patient monitoring system. Fog computing is an extended version of the cloud computing paradigm, which is suitable for reliable, delay-sensitive life-critical applications. In addition, to enhance the performance of the network, an energy-efficient minimum cost parent selection algorithm has been proposed for routing data packets. The dynamic time slot allocation uses fuzzy logic with input variables as energy ratio, buffer ratio, and packet arrival rate. Dynamic slot allocation eliminates the time slot wastage, excess delay in the network and attributes a high level of reliability to the network with maximum channel utilization. The efficacy of the proposed scheme is proved in terms of packet delivery ratio, average end to end delay, and average energy consumption when compared with the conventional IEEE 802.15.4 standard and the tele-medicine protocol.

Controlled Solar Powered Irrigation System Based on GSM and Solar Panel

These days, irrigation system are generally utilized in agricultural field to lessen the dependency on rain, the vast majority of irrigation system are either having time based automation or directed manually. In these sorts of system water is applied to field based on fixed timeslots which required high labour for observing and furthermore it decreases the field efficiency. This fixed time slot working prompts over irrigation than the real plant requirement and under irrigation when plants required more water in their peak periods. Fall in crop growth rate, late blooming and decrease of the yield are the main faults caused because of water lack. Besides, over irrigation in the root zones prompts sickness of the root zones and vegetation, extra expense for agriculturist, wasting of water and time wastage. Additionally saltiness of the soil can be increased by ceaseless supply of excess water. For working of irrigation system, power is required. So utilization of sun energy for power generation is necessary to handle current energy crises. The main shortcomings of the fixed panel solar system is that because of rotation of the sun, it can't extract most extreme energy from the sun. Solar power based smart irrigation system are solutions to the Indian farmer. This system comprises of sunlight based water pumps along with an automatic water flow control utilizing a moisture sensor and GSM technology. It is the proposed answer for the present emergency condition for the Indian farmers. This system saves power by decreasing the utilization of grid power and monitors water by lessening water misuses. In GSM mode the farmer at his very own place can send instruction to ON and OFF the water supply through pump without really going to the field.

Capacity Planning of Electric Car Charging Station Based on Discrete Time Observations and MAP(2)/G/c Queue

The modeling of electric car charging stations is essential for determining the required number of chargers in order to ensure the required service quality. In this paper we propose a new estimation method for the stochastic modeling of electric car charging stations, based on Markov arrival process (MAP).The input of the proposed model is empirical data for the arrival and service process of electric cars, given as histograms: the number of arriving cars during a fixed time slot (5 minutes in our case) and the histogram of service times (in 5 minutes granularity). The fact that observations on the continuous time process of car charging are available in discrete time steps poses a modeling challenge, which was not considered before. We propose a procedure to fit the observed data with a continuous time MAP of order 2 such that three moments and a correlation parameter of the discrete time observations are matched with three moments and the correlation parameter of the continuous time MAP for the given time interval. We implemented the fitting procedure in MATLAB and verified the obtained model of car charging station against simulation. As the MAP model of the arrival processes is reasonably close to the observations, the obtained MAP/G/c queue allows a more accurate dimensioning of car charging station than the previously applied ones.

Deep-Learning-Assisted Network Orchestration for On-Demand and Cost-Effective vNF Service Chaining in Inter-DC Elastic Optical Networks

This work addresses the relatively long setup latency and complicated network control and management caused by on-demand virtual network function service chain (vNF-SC) provisioning in inter-datacenter elastic optical networks. We first design a provisioning framework with resource pre-deployment to resolve the aforementioned challenge. Specifically, the framework is designed as a discrete-time system, in which the operations are performed periodically in fixed time slots (TS). Each TS includes a pre-deployment phase followed by a provisioning phase. In the pre-deployment phase, a deep-learning (DL) model is designed to predict future vNF-SC requests, then lightpath establishment and vNF deployment are performed accordingly to pre-deploy resources for the predicted requests. Then, the system proceeds to the provisioning phase, which collects dynamic vNF-SC requests from clients and serves them in real-time by steering their traffic through the required vNFs in sequence. In order to forecast the high-dimensional data of future vNF-SC requests accurately, we design our DL model based on the long/short-term memory-based neural network and develop an effective training scheme for it. Then, the provisioning framework and DL model are optimized from several perspectives. We evaluate our proposed framework with simulations that leverage real traffic traces. The results indicate that our DL model achieves higher request prediction accuracy and lower blocking probability than two benchmarks that also predict vNF-SC requests and follow the principle of the proposed provisioning framework.

Dimensioning of the Store-and-Transfer WDM Network With Limited Node Storage Under the Sliding Scheduled Traffic Model

The so-called store-and-transfer WDM network (STWN) can store data in source storage and provision lightpaths at an optimal time when wavelengths are clear of conflicts. Consequently, blocking of requests can be reduced and resource utilization of the network can be improved. In this work, we investigate dimensioning of STWN and propose a two-step method to jointly determine the number of wavelengths and storage size required to satisfy the demand, which is given as a load matrix with a deadline, blocking rate, and wavelength utilization. The method models the STWN as a TDM network and first obtains the required storage size by maximizing the number of fixed time slots in each period, then calculates the required number of wavelengths with the number of time slots. Numerical results show the following: high load between far apart source and destination nodes has significant impact on the required wavelengths and storage. For instance, in a 24-node topology, 20% more wavelengths and storage may be required to satisfy a biased load matrix than a randomly generated one. When calculating the required number of wavelengths, ourmethod outperforms traditional routing and wavelength assignment (RWA), because the TDM-based model supports fractional load. In the 24-node topology, 18% more wavelengths may be required byRWA than by our method. By installing amoderate amount of storage,wavelength utilization can be effectively improved. With number of wavelengths and storage size equaling 29 and 274, in the 24-node topology, utilization can reach 0.9. We also find wavelength is equivalent with storage regarding capacity of a STWN. For instance, with number of wavelengths and storage size equaling 114 and 131, in the 24-node topology, the blocking rate is the same as with number of wavelengths and storage size equaling 29 and 270.

Joint Provisioning of Lightpaths and Storage in Store-and-Transfer Wavelength-Division Multiplexing Networks

So-called store-and-transfer wavelengthdivision multiplexing networks (STWNs) can store data and provision lightpaths at an optimal time when the wavelengths are clear of conflicts. If the wavelength utilization of the wavelength-division multiplexing network is not uniform, the embedded storage nodes can store data and the lightpath is segmented so conflicts along separate segments of the lightpath can be resolved independently. Consequently, blocked requests can be reduced, and the resource utilization of the network can be improved. In this work, we investigate three extensions of the sliding scheduled traffic model, which is a variant of advance reservations. First, we segment a lightpath with embedded storage nodes, split the transfer window into smaller ones, and sequentially assign a smaller window to each segment of the lightpath. Each segment of the lightpath has fewer hops, and thus, overall blocking can be decreased. Second, we allocate fixed time slots in continuous frames over multiple wavelengths for a time-division multiplexing (TDM) mode large data transfer. The resource allocations are more flexible in resolving conflicts, and thus, blocking can be decreased. Third, we use segmented lightpaths and TDM mode transfer along each segment of the lightpath. Since the first two extensions are orthogonal, the combination can decrease the blocking further. We propose four heuristic algorithms to evaluate the extensions. We also propose two parallel implementations of the four heuristic algorithms. The simulations show the following: the provisioning algorithms for the first two extensions have similar performances, and both decrease blocking by 20%. If the service time is long, the second one performs better. The provisioning algorithm for the last extension decreases blocking by 40%. The first extension requires 10% more storage, and the second extension requires 20% less storage. Under a large load and with 8 CPUs, the parallel implementations improve the speed by three times. It also shows that the number of time slots per frame influences the performance; the influence is not monotonic; and, if the value increases too much, the blocking rate increases by 20% and the storage size increases by 30%.

Bandwidth Resource Sharing on the XG-PON Transmission Convergence Layer in a Multi-operator Scenario

Passive optical networks (PONs) offer high network capacity and densified coverage at the cost of high capital expenditure. Therefore, it is desirable for network operators who deploy their own infrastructures to share their PON infrastructures to reduce the initial investment. The key problem of PON network sharing is how to balance the trade-off between isolation and utilization of bandwidth resources. In this paper,we introduce a bandwidth resourcesharing framework in XG-PONs (10 gigabit-capable PONs) amongmultiple operators. In this framework, each transmission convergence (TC) frame with fixed time slots (125 μs) is regarded as a bandwidth slice, which is the resource granularity for sharing. Then, we formulate the bandwidth resource-sharing problem and propose slice scheduling schemes to assign bandwidth slices to different operators. Our proposed schemes meet three key requirements of network sharing: isolation, customization, and efficient resource utilization. We study the efficacy of our schemes by employing an event-driven simulator. The results show our schemes could ensure resource isolation across operators andmaximize total resource utilization while providing the flexibility of running different customized algorithms to different operators.

A Self-adaptive Time Slot Allocation Algorithm Based Low Value of SINR in TD-LTE System

In time division duplex Long Term Evolution (TD-LTE) system, the protocol provides 7 different time slot configurations. Only one fixed time slot deployed in mobile network. This paper proposed a dynamic time slot allocation algorithm, the system according to the user equipment (UE) detected the environmental signal to interference and noise ratio (SINR) to dynamically decide the time slot configuration, especially the UE in the situation of relatively bad wireless environment and the lower SINR value, can adopt the polling algorithm, obtained the dynamic time slot configuration. This method is simple in calculation, can reduce redundant computational burden in the system. The result of simulation demonstrated that the algorithm has significant effect in improving the networking throughput、increasing the system spectrum utilization rate.

RFID 시스템에서 4 슬롯을 이용한 충돌방지 알고리즘

In this paper, we propose tree-based hybrid query tree architecture utilizing time slot. 4-Bit Pattern Slot Allocation(4-SL) has a 8-ary tree structure and when tag ID responses according to query of the reader, it applies a digital coding method, the Manchester code, in order to extract the location and the number of collided bits. Also, this algorithm can recognize multiple Tags by single query using 4 fixed time slots. The architecture allows the reader to identify 8 tags at the same time by responding 4 time slots utilizing the first bit([prefix+1], F ∈ {‘0’ or ‘1’}) and bit pattern from second ~ third bits([prefix+2] ~ [prefix+3], B2 ∈ {“00” or “11”}, B1 ∈ {“01” or “10”}) in tag ID. we analyze worst case of the number of query nodes(prefix) in algorithm to extract delay time for recognizing multiple tags. The identification ∙제1저자 : 김용환 ∙교신저자 : 정경호 ∙투고일 : 2014. 11. 15, 심사일 : 2014. 11. 25, 게재확정일 : 2014. 12. 3. * 경운대학교 컴퓨터공학과(Dept. of Computer Engineering, Kyungwoon University) ** 경운대학교 모바일공학과(Dept. of Mobile Engineering, Kyungwoon University) 112 Journal of The Korea Society of Computer and Information December 2014 delay time of the proposed algorithm was based on the number of query-responses and query bits, and was calculated by each algorithm. ▸

Unadvertised energy saving method for static and homogeneous wireless sensor networks

Several approaches have been proposed to increase the lifetime of a wireless sensor network (WSN) while preserving full coverage of the sensed area. Most of them employ protocols to reduce the energy consumption by switching the sensors off. To correctly decide the set of nodes to switch off without losing the full network coverage, these techniques must guarantee that all nodes have up-to-date information about their neighbours. Considering a static WSN, the only important information which must be regularly advertised is the energy level of the nodes. This information is exchanged between nodes in fixed time slots through one-hop messages. Nevertheless, the energy spent to transmit one simple bit of information is as the same used to process hundreds of transactions in a typical sensor. Thus, reducing the communication between nodes leads to an increase in the energy saving. This study proposes the unadvertised round energy saving (u-REST) algorithm which eliminates the energy level advertise messages, thus conserving a huge amount of energy. u-REST is able to increase the energy savings by deciding the set of nodes which can be switched off while preserving full area coverage without using energy level advertise messages. Mathematical proofs demonstrate that u-REST ensures a full coverage of the interest area while saving energy. In fact, it is mathematically demonstrated that the worst case for energy savings in u-REST is able to preserve more energy than the best case of all synchronisation-based methods.

Heuristics for scheduling a two-stage hybrid flow shop with parallel batching machines: application at a hospital sterilisation plant

The model of a two-stage hybrid (or flexible) flow shop, with sequence-independent uniform setup times, parallel batching machines and parallel batches has been analysed with the purpose of reducing the number of tardy jobs and the makespan in a sterilisation plant. Jobs are processed in parallel batches by multiple identical parallel machines. Manual operations preceding each of the two stages have been dealt with as machine setup with standardised times and are sequence-independent. A mixed-integer model is proposed. Two heuristics have been tested on real benchmark data from an existing sterilisation plant: constrained size of parallel batches and fixed time slots. Computation experiments performed on combinations of machines and operator numbers suggest balancing the two stages by assigning operators proportionally to the setup time requirements.

Real-time Ethernet based on passive optical networks

Guiling WuFeirang SuXinwan LiWeiwen ZouJianping ChenShanghai Jiao Tong UniversityDepartment of Electronic EngineeringState Key Laboratory of Advanced OpticalCommunication Systems and NetworksShanghai 200240, ChinaE-mail: wuguiling@sjtu.edu.cnAbstract. A passive optical network (PON) based real-time Ethernet(PONRTE), which can take advantage of PON features such as broadbandwidth, high reliability, and easy maintenance to satisfy the determi-nation and real-time requirements of high performance industrial applica-tions, is proposed. The protocol model and network architecture having acompatiblephysicallayerandMAClayerwithEthernetpassiveopticalnet-work are presented for the proposed PONRTE. A fixed periodic time slotallocation mechanism including a synchronic time division multiplexingtransmission and an asynchronic data transmission is adopted to guaran-tee the determination and real-time of the communication. A simple andeasy to implement time synchronization approach, where the starting timeof the first transmission slot of an access node is synchronized by a rel-ative time synchronization while the starting time of subsequent slots isdetermined by the fixed period and a dynamic time synchronization, isdesigned to support the fixed time slot allocation mechanism and avoidthe collision in PONRTE. A 100 Mb∕s PONRTE experimental testbedwith 16 access nodes and a time allocation period of 240 μs is demon-strated. The results show that the experimental PONRTE can work stablyand reliably with a frame loss ratio less than 10

Joint cooperative relay scheme for spectrum-efficient usage and capacity improvement in cognitive radio networks

In order to improve the efficiency of spectrum resource usage and the capacity of wireless networks, cooperative relay techniques which utilize the vacant spectrum of primary users for secondary users' data transmission have been applied in cognitive radio networks. Considering the dynamic time-varying vacant spectrum resources and achievable rate on different channels at relay nodes (RN), the traditional fixed time slot allocation scheme for cooperative RNs has the bottleneck for further improving the spectrum usage efficiency and system throughput. Therefore, the joint cooperative relay scheme with RN selection, channel allocation and dynamic time slot allocation (DyTSA), is designed to increase the spectrum usage efficiency and system capacity by dynamic tuning DyTSA ratio to adapt to the changing radio environment in multiple RNs serving multiple destinations scenario. Propositions of the proposed scheme are proved theoretically by closed-form solutions. Numerical results verify the effectiveness and correctness of the proposed scheme.

An Adaptive IEEE 802.15.4a TH-TDMA UWB Industrial Field Level Network

We introduce the deployment of IEEE 802.15.4a in industrial field level communication, which is unexplored so far. Impulse radio-time hopping ultra wide band (IR-TH UWB) physical layer is robust against dense multipath fading and interferences. However, we propose an adaption in medium access control (MAC) to meet the major constraints of reliability and timeliness. The self configuring MAC overcomes the difficulties and limitations of specified carrier sense multiple access/collision avoidance (CSMA/CA), slotted Aloha and guaranteed time slots (GTS) mechanisms. Addressable TH codes in fixed time slots of modified superframe structure are used to handle asynchronous alarm requests during ongoing synchronous transmissions. Traffic modeling is presented and we derive the expressions for accessing delays of both the synchronous and asynchronous data traffics. The realistic industrial non line of sight (NLOS) channel environment of IEEE 802.15.4a is employed and the respective power delay profile (PDP) and cumulative density function (CDF) of instantaneous signal to noise ratio (SNR) are found. Moreover, for large number of resolvable multipath components (MPCs), we also propose a reduced complexity adaptive SRake receiver, which efficiently recovers the weak IR-TH UWB signals in dense multipath propagation and strong noise. In addition, we evaluate the error performance of the proposed receiver architecture in comparison with conventional SRake and additive white Gaussian noise (AWGN) correlation receivers. Our simulation results show a significant performance improvement with very less number of SRake fingers.

Spike synchronization of chaotic oscillators as a phase transition

We study how a locally coupled array of spiking chaotic systems synchronizes to an external driving in a short time. Synchronization means spike separation at adjacent sites much shorter than the average inter-spike interval; a local lack of synchronization is called a defect. The system displays sudden spontaneous defect disappearance at a critical coupling strength suggesting an existence of a phase transition. Below critical coupling, the system reaches order at a definite amplitude of an external input; this order persists for a fixed time slot. Thus, the array behaves as an excitable-like system, even though the single element lacks such a property.

A new approach to bridging content gaps in the clinical curriculum

Background: In 2004–05 Tulane University School of Medicine implemented a longitudinal Interdisciplinary Seminar Series composed of small-group interactive exercises to address topics that are often overlooked during the clinical education of medical students. The series utilizes five adult learning principles.Methods: Each of 13 seminars is offered at a fixed time slot, repeated two to six times per year. Students are required to attend a minimum of five seminars, of their choice, during years three and four. Students access an online pre-enrollment system that maximizes learning opportunities by limiting the number of participants. Seminars emphasize active learning with small-group problem-solving exercises and multiple interactive techniques. Clinical vignettes, standardized patients, journal articles, and case-based learning are among the learning methods.Results: Seminar evaluations showed strong support in program content and effectiveness (mean = 4.47 on a five-point scale), facilitators (4.63), and learning opportunities (4.51). Additionally, students strongly endorsed individual seminars to classmates (4.47). Twelve of 13 (92%) seminars received scores higher than 4.0 for program content and effectiveness, facilitators and learning opportunities.Conclusions: The Interdisciplinary Seminar Series has been a valuable addition to the Tulane clinical curriculum. Students report that the success of the series is due to: (a) their ability to select seminars based on their individualized interests and needs; and (b) faculty development of student-centered seminars with active learning opportunities. This Seminar Series differs from interclerkship initiatives at other medical schools where topics are offered less frequently and to a class as a whole. Tulane's program is a longitudinal intervention with multiple opportunities for student participation during their clinical education. Seminars are repeated to allow greater flexibility in student scheduling. Seminar discussions are rich in content since attendees include both third- and fourth-year students with variable levels of clinical skills and experiences.

Establishment of transcriptional competence in early and late S phase.

In animal cells, the process of DNA replication takes place in a programmed manner, with each gene region designated to replicate at a fixed time slot in S phase. Housekeeping genes undergo replication in the first half of S phase in all cell types, whereas the replication of many tissue specific genes is developmentally controlled, being late in most tissues but early in the tissue of expression. Here we employ nuclear DNA injection as an experimental system to test whether this phenomenon is due to differences in the ability to set up transcriptional competence during S phase. Our results show that, regardless of sequence, exogenous genes are a better template for transcription when injected into nuclei of cells in early as opposed to late S phase, and this expression state, once initiated, is preserved after cell division. DNA injected in late S phase is apparently repressed because it is packaged into chromatin containing deacetylated histones, and the same is true for late replicating chromosomal DNA. These findings suggest a mechanistic connection between replication timing and gene expression that might help to explain how epigenetic states can be maintained in vivo.