Utilization of idle time slot in spectrum sensing under noise uncertainty

<p>Spectrum sensing in cognitive radio (CR) is a critical process as it directly influences the accuracy of detection. Noise uncertainty affects the reliability of detecting vacant holes in the spectrum, thus limiting the access of that spectrum by secondary users (SUs). In such uncertain environment; SUs sense the received power of a primary user (PU) independently with different measures of signal-to-noise ratio (SNR). Long sensing time serves in mitigating the effect of noise uncertainty, but on the cost of throughput performance of CR system. In this paper, the scheme of an asynchronous and crossed sensing-reporting is presented. The scheme reduces energy consumption during sensing process without affecting the detection accuracy. Exploiting the included idle time (𝑇𝑖) in sensing time slot; each SU collects power samples with higher SNR directly performs the reporting process to a fusion center (FC) consecutively. The FC terminates the sensing and reporting processes at a specific sensing time that corresponds to the lowest SNR (𝑆𝑁𝑅𝑤𝑎𝑙𝑙). Furthermore, this integrated scheme aims at optimizing the total frame duration (𝑇𝑓). Mathematical expressions of the scheme are obtained. Analytical results show the efficiency of the scheme in terms of energy saving and throughput increment under noise uncerainty.</p>

Distributed Periodic Steady State Kalman Filter

In this paper a distributed implementation for the periodic steady state Kalman filter is proposed. The distributed algorithm has parallel structure and can be implemented using processors in parallel without idle time. The number of processors is equal to the model period. The resulting speedup is also derived. The Finite Impulse Response (FIR) form of the periodic steady state Kalman filter is derived.

Low I/O Intensity-aware Partial GC Scheduling to Reduce Long-tail Latency in SSDs

This article proposes a low I/O intensity-aware scheduling scheme on garbage collection (GC) in SSDs for minimizing the I/O long-tail latency to ensure I/O responsiveness. The basic idea is to assemble partial GC operations by referring to several determinable factors (e.g., I/O characteristics) and dispatch them to be processed together in idle time slots of I/O processing. To this end, it first makes use of Fourier transform to explore the time slots having relative sparse I/O requests for conducting time-consuming GC operations, as the number of affected I/O requests can be limited. After that, it constructs a mathematical model to further figure out the types and quantities of partial GC operations, which are supposed to be dealt with in the explored idle time slots, by taking the factors of I/O intensity, read/write ratio, and the SSD use state into consideration. Through a series of simulation experiments based on several realistic disk traces, we illustrate that the proposed GC scheduling mechanism can noticeably reduce the long-tail latency by between 5.5% and 232.3% at the 99.99th percentile, in contrast to state-of-the-art methods.

Triangular intuitionistic fuzzy sequencing problem

In this paper, we discuss different types of fuzzy sequencing problem with Triangular Intuitionistic Fuzzy Number. Algorithm is given for different types of fuzzy sequencing problem to obtain an optimal sequence, minimum total elapsed time and idle time for machines. To illustrate this, numerical examples are provided.

Produktivitas Peralatan Konstruksi Pada Proyek Jaringan Irigasi D.I Baliase Kanan 2 (Paket IV) Kabupaten Luwu Utara

Penggunaan peralatan konstruksi sangat berpengaruh terhadap pekerjaan di dunia teknik sipil, dalam hal ini khususnya alat berat. Sebagai upaya peningkatan produksi pertanian di provinsi Sulawesi Selatan, kementrian Pekerjaan Umum dan Perumahan Rakyat (PUPR) semakin memperluas jaringan irigasi yang sumbernya berasal dari bendungan baliase di Kabupaten Luwu Utara. Pada pembangunan jaringan irigasi ini, proses pekerjaan masih pada tahap penghamparan dan pemadatan tanah yang menggunakan 4 alat berta yaitu Excavator, Dump Truck, Dozzer, dan Vibrator Roller. Penelitian ini dilakukan dengan metode kuantitatif dengan cara pengamatan langsung dilapangan. Pengolahan data dilakukan untuk mengetahui produktivitas dari masing-masing alat dan melihat apakah peralatan yang digunakan pada pekerjaan penghamparan dan pemadatan tanah ini sinkron. Berdasarkan hasil penelitian diketahui produktivitas Excavator sebesar 631,299 m3/jam, DumpTruck sebesar 335,69 m3/jam, Dozer 603,405 m3/jam, dan Vibrator Roller 4987,5511 m3/jam. Dari hasil dapat dilihat bahwa produktivitas pada peralatan yang digunakan tidak sinkron yang mengakibatkan terjadinya Idle Time pada beberapa alat, oleh karena itu dilakukan perhitungan sinkronisasi alat . Dari hasil perhitungan didapatkan bahwa terjadi penambahan alat pada Dump Truck sebanyak 10 unit agar mengurangi idle time pada peralatan konstruksi.

Modeling of material flow management processes in the formation of transport logistics chains

The article proposes a mathematical model for optimizing the interaction of road and sea transport. The model allows to optimize the process of material flow management in the formation of transport logistics chains. The solution to this problem is especially important given the observed growth of competition between operators carrying out cargo transportation along international transport corridors. The application of the model is aimed at reducing the idle time of both vehicles waiting for unloading in the port, and reducing the idle time of ships awaiting loading of ships in ports. The relevance of using the proposed model is based on the constant growth of cargo traffic going through the ports, as well as the existing restrictions expressed in the lack of space for storing goods in anticipation of the arrival of ships in most modern ports participating in international cargo transportation, in addition, an important factor is that in most of these ports the time the passage of trucks to the port is regulated by certain hours of the day.

Channel Occupancy Measurements in 868 MHz ISM Band in Residential Areas

The rapid development of Internet of Things (IoT) has led to more and more devices using ISM frequency bands. Because they are not time synchronized, medium access collisions are unavoidable. The probability of such a collision is usually reasonably low; however, it increases with the number of transmitters competing for the same frequency channel. For this reason, ISM bands’ occupancy is regularly monitored by researchers. This paper presents the results of the measurement campaign during which a selected part of the 868 MHz ISM frequency band was monitored for the presence of transmissions in six locations in various residential areas in Warsaw, Poland. For the purpose of the campaign, a dedicated measurement set-up comprising a software-defined radio (SDR) module was assembled. The measurements results showed that the channel occupancy is in most cases lower than 1% with a maximum observed value of 2%. The paper presents selected characteristics of the detected signals. Additionally, distribution over time of the detected signals was used together with the Monte Carlo simulations to analyze how long idle time blocks are available for new transmitters that could be deployed in the band under testing.

Dynamic Surgery Scheduling Based on an Improved Genetic Algorithm

We formulated a new stochastic programming formulation to solve the dynamic scheduling problem in a given set of elective surgeries in the day of operation. The problem is complicated by the fact that the exact surgery durations are not known in advance. Elective surgeries could be performed in parallel in a subset of operating rooms. The appointment times and assignments of surgeries were planned by an experienced nurses in advance. We present a mathematical model to capture the nature of dynamic scheduling problem. We propose an efficient solution based on an improved genetic algorithm (IGA). Our numerical results showed that dynamic scheduling with the IGA improves the resource utilization as measured by surgeon waiting time and operation room idle time.

What to do when there is nothing to do? Toward a better understanding of idle time at work

Idle time at work is a phase of involuntary downtime during which employees experience that they cannot carry out their work tasks. In contrast to breaks, interruptions, procrastination, or withdrawal behavior, employees cannot work because of the absence of work-related tasks. Based on action regulation theory, we develop an integrative conceptual model on the antecedents and consequences of the subjective experience of idle time. We propose that work constraints (i.e., regulation problems) have negative effects on occupational well-being and task performance, and that these effects are mediated by subjective idle time. The strength of these effects is further assumed to be influenced by individuals’ use of proactive (i.e., prevention) and adaptive (i.e., coping) strategies. Results of a supplemental qualitative study, for which we interviewed 20 employees from different occupations, provided preliminary support for the propositions. Finally, we develop theory on how individual, situational, and organizational characteristics may influence the proposed effects on and of idle time. Overall, this conceptual development paper contributes to a better theoretical understanding of idle time at work by extending its definition and applying action regulation theory to this practically important phenomenon.