Multiple Channel Systems Research Articles

Study of irrigation aspect in the interconnection system of Telaga Tanjung and Singin Ponds in Tabanan Regency

Interconnection is a channel that links multiple water channel systems with those downstream of a river area. The proposed system will utilize existing canals in Gadungan, Matan, and Unun Irrigation Areas, extending to the Lambuk Reservoir dam system. The problem is that irrigation areas downstream of the Lambuk Reservoir are Lambuk (726 ha), Babakan Anyar (42 ha), and Lanyah (281 ha) experience water shortages (planting intensity of 170% to 200%) during the dry season. The study utilized water balance methods in rice fields, the basic year method for main discharge at weirs, and interconnection channel analysis for water needs calculation. From the water balance analysis, the Singin System cannot make a new interconnection channel to the Lambuk Reservoir because the available water in each reservoir can only irrigate the Matan and Unun Irrigation Areas. From the Telaga Tunjung System, there is still a lot of water available, especially during the rainy season, so that it can supply the reservoir for the Lambuk Reservoir. This means that the interconnection system from this reservoir still needs to be created from the primary channel of the Gadungan Irrigation Area.

On the Convex Hull of the Achievable Capacity Region of the Two User FDM OMA Downlink

In multiple access channel systems, such as a mobile communication network, it is important to determine how to share the available resources (for example bandwidth and power) among the users. In recent years, one of the promising scheme is Non-Orthogonal Multiple Access (NOMA), where, unlike the traditional Orthogonal Multiple Access, OMA solution, signals for the different users overlap in some domain (power-domain NOMA, code-domain NOMA, etc). In order to evaluate the performance of any NOMA scheme, we need to compare the achievable bit rates of the users (the capacity region) to an OMA case with comparable parameters (for example, same total bandwidth, same total power and same channel conditions, etc). To make this comparison, we first need to know the capacity region for the OMA cases. Many papers make such comparison without detailing the derivation of the capacity region of the OMA case they compare to [1], [2], [3], [4]. In some cases, we have only one free parameter to choose (for example in uplink frequency division multiplexing systems for two users, it is the bandwidth ratio between the users), and the achievable capacity can be directly calculated for both users depending on the single parameter (hence the boundary of the capacity region is trivial). In other cases, such as downlink frequency division multiplexing systems, even for only two users, we have to allocate optimally two resources between the users: the bandwidth and the base station’s available power. Hence, it is far from being trivial to determine which combination is better and where the boundary of the capacity region is. In this paper, we provide a derivation for that case.

Vertical and horizontal governance in multiple-channel systems

Multiple-channel systems have several characterizing dimensions, as they encompass the concepts of multiple and dual channels. However, neither has been unambiguously distinguished. To clarify this difference, this study separates multichannel system dimensions into two categories: channel variety and duality. We examine how these two dimensions influence vertical and horizontal relationship governance in multichannel systems using survey data from industrial manufacturers. The results of our study show that vertical and horizontal governance positively affect channel performance, and that channel variety has a moderating role in weakening the performance effect of vertical governance, while channel duality strengthens this effect. Thus, the findings imply that diversifying channel types makes channel management difficult for manufacturers because of the negative moderating effect of this strategy. Meanwhile, the analytical results on the positive moderating effect of channel duality imply that the concurrent deployment of integrated and independent channels assists in vertical governance between manufacturers and intermediaries.

3D-Printed Self-Healing Elastomers for Modular Soft Robotics.

Advances in materials, designs, and controls are propelling the field of soft robotics at an incredible rate; however, current methods for prototyping soft robots remain cumbersome and struggle to incorporate desirable geometric complexity. Herein, a vat photopolymerizable self-healing elastomer system capable of extreme elongations up to 1000% is presented. The material is formed from a combination of thiol/acrylate mixed chain/step-growth polymerizations and uses a combination of physical processes and dynamic-bond exchange via thioethers to achieve full self-healing capacity over multiple damage/healing cycles. These elastomers can be three dimensional (3D) printed with modular designs capable of healing together to form highly complex and large functional soft robots. Additionally, these materials show reprogrammable resting shapes and compatibility with self-healing liquid metal electronics. Using these capabilities, subcomponents with multiple internal channel systems were printed, healed together, and combined with functional liquid metals to form a high-wattage pneumatic switch and a humanoid-scale soft robotic gripper. The combination of 3D printing and self-healing elastomeric materials allows for facile production of support-free parts with extreme complexity, resulting in a paradigm shift for the construction of modular soft robotics.

Overbank sediment waves in the southern Taranaki Basin, New Zealand

In the southern Taranaki Basin, a thick stratigraphic sequence of late Miocene age is well imaged by modern 3D seismic data. Within this sediment package, the evolution of multiple deepwater channel systems are preserved and interpreted. Anomalous features located between channel complexes are identified in both map-view and vertical sections. Extracting selected seismic attributes along interpreted horizons and using in context geologic knowledge suggests these anomalous features are overbank sediment waves resulting from overbank sedimentation. Alternate interpretations are also presented, such as slump scarps and progradational clinoforms. The evidence aims at improving our identification of these deepwater depositional elements. Geological feature: Overbank sediment waves in the southern Taranaki Basin, New Zealand Seismic appearance: Shingled, undulating, downlapping reflectors Alternative interpretations: Prograding clinoforms; slump scarps Features with similar appearance: Prograding clinoforms Formation: Mount Messenger Formation, Taranaki Basin Age: Late Miocene Location: Taranaki Basin, New Zealand Seismic data: Hector-3D Contributors: Clayton Silver and Dr. Heather Bedle Analysis tools: Schlumberger’s Petrel software was used for seismic interpretation and visualization; Attribute-Assisted Seismic Processing & Interpretation (AASPI) was utilized for computation of seismic attributes.

Liquid blockage and flow maldistribution of two-phase flow in two parallel thin micro-channels

In this study, flow maldistribution in a system of two parallel thin micro-channels with shared inlet and outlet manifolds is experimentally investigated with one channel subject to single-phase flow and the other to two-phase one. The flow pattern, pressure drop, gas flow rate in the single-phase flow channel Q1 and two-phase flow channel Q2 are studied. Film flow patterns are observed for all the cases of the study, consistent with literature work. The Q2Q1 ratio is defined as a direct measure to flow maldistribution. Theoretical derivation shows that Q2Q1 is inverse of the two-phase multiplier ϕ or Q2Q1=1ϕ. Three levels of liquid flow rate are examined and presented to show three representative trends: (1) For the highest water flow rate, i.e. 10−2 m/s, Q2Q1 is found to monotonically increase with the air flow rate, with its value Q2Q1 as low as about 0.2 at 0.86 m/s gas velocity and approaching 0.65 at 3.44 m/s. (2) For the lowest water velocity, i.e. 10-4 m/s, Q2Q1 shows decrease at first, followed by an increase, as the superficial gas velocity increases from 0.86 m/s to 3.44 m/s. It reaches about 0.76 at 0.86 m/s gas velocity and drops to about 0.55 at 1.72 m/s. (3) For the intermediate water velocity, i.e. 10-3 m/s, two “steady” states are identified at 0.86 m/s gas velocity with one having Q2Q1 as high as about 0.69 and the other about 0.52. The rest follows a similar trend as 10-4 m/s liquid velocity. The observed two “steady” states and changing trend at the two low liquid velocities may be due to the altered liquid blockage near the channel exit. It is also indicated that the two-phase multiplier ϕ obtained in single channel testing may not be used to measure flow maldistribution in multiple-channel systems. The work is important to study of two-phase flow, multi-channel design, flow maldistribution, and flow control in micro-channels for PEM fuel cells, electrolyzers, and thermal devices.

Minding the competition: The drivers for multichannel service quality in fashion retailing

PurposeConsumer purchasing behaviour has changed substantially in the light of recent developments in E-Commerce. So-called ‘multichannel customers’ tend to switch retail channels during the purchasing process. In order to address changing consumer behaviours, multichannel fashion retailing companies must continue to learn how to provide excellent service to such customers. Drawing on expectation confirmation theory, this paper investigates drivers for service quality from the perspective of multichannel fashion customers. Design/methodology: This paper approaches the topic of multichannel service quality by adopting a social constructionist research paradigm, utilising an abductive approach and an embedded case study research strategy. It aims to explore the lived experiences and perspectives of individuals in the context of an evolving complex and multidimensional phenomenon. The paper seeks information-rich cases and therefore views service quality through the eyes of experienced German multichannel customers. A customer perspective helps to explain the phenomenon of multichannel service quality and helps to disclose the meaning that these customers give to it. The sample size for this research consisted of 18 in-depth interviews and two focus groups including ten focus group participants. As such, a process of methodological triangulation was followed. FindingsIntegration quality is identified as the essence of competitive advantage for multichannel retailers. The paper conceptualises integration quality as a catalyst, which plays a supporting role in reinforcing the reactions of the physical and electronic service quality in order to provide an optimised service quality experience. Originality/valueThis paper looks at retailer/customer interactions in the context of purchases of a fashion product at a retailer using different retail channels. It highlights the distinctive requirements of multiple-channel systems within which the focus should not only be to enhance and improve physical and/or electronic service quality, but must also be about the integration of the service offers of each channel. The paper contributes to the interpretation of multichannel service quality with a new concept that explains the phenomenon from the perspective of customers.

Energy Efficiency, Spectral Efficiency and Delay Analysis for Selective ARQ Multichannel Systems

In this paper, we develop selective retransmission schemes for multiple-channel systems. The proposed schemes are selective automatic repeat request with fixed bandwidth, selective chase combining with fixed bandwidth, limited selective chase combining with fixed bandwidth and selective automatic repeat request with variable bandwidth. The main objective of the proposed schemes is to use the available power and bandwidth budget effectively along with selective retransmission to deliver the required data successfully within a limited number of transmissions. To investigate the performance of each scheme, we first analyze and derive closed-form expressions for the average spectral efficiency (SE), energy efficiency (EE) and delay for each scheme. Then, we compare the EE, SE and delay performance of each scheme versus different system parameters through numerical results.

A Multiinput Bridgeless Resonant AC–DC Converter for Electromagnetic Energy Harvesting

Flapping electromagnetic-reed generators are investigated to harvest wind energy, even at low cutoff wind speeds. Power electronic interfaces are intended to address ac–dc conversion and power conditioning for single- or multiple-channel systems. However, the generated voltage of each generator reed at low wind speed is usually below the threshold voltage of power electronic semiconductor devices, increasing the difficulty and inefficiency of rectification, particularly at relatively low output powers. This paper proposes a multiinput bridgeless resonant ac–dc converter to achieve ac–dc conversion, step-up voltage and match optimal impedance for a multichannel electromagnetic energy harvesting system. Alternating voltage of each generator is stepped up through the switching LC network and then rectified by a freewheeling diode. Its resonant operation enhances efficiency and enables miniaturization through high frequency switching. The optimal electrical impedance can be adjusted through resonance impedance matching and pulse-frequency-modulation control. A 5 cm × 3 cm, six-input standalone prototype is fabricated to address power conditioning for a six-channel wind panel.

H∞ filtering for multiple channel systems with varying delays, consecutive packet losses and randomly occurred nonlinearities

In this paper, we deal with the H∞ filtering problem for a class of multiple channel network-based systems. The system under consideration contains random varying delays, consecutive packet losses, as well as sector-bounded nonlinearities with random occurrence. A group of mutually independent stochastic variables satisfying Bernoulli distributions is introduced to model the addressed system. A linear full-order filter is designed such that, in the presence of all admissible time delays, packet losses and random nonlinearities, the dynamics of the filtering error is guaranteed to be exponentially stable in the mean square sense, and the prescribed H∞ disturbance rejection attenuation level is also achieved. Sufficient conditions are established for the existence of the desired filters. The explicit expression of the desired filter gains can be obtained by solving the feasibility of a linear matrix inequality (LMI). The illustrative examples are given to demonstrate the effectiveness of the proposed method.

Analysis of controls upon channel planform at the First Great Bend of the Upper Yellow River, Qinghai-Tibet Plateau

The 270 km long section of the Upper Yellow River at the First Great Bend is comprised of single channel and multiple channel systems that alternate among anastomosing, anabranching, meandering and braided reaches. The sequence of downstream pattern changes is characterized as: anastomosing-anabranching, anabranching-meandering, meandering-braided and braided-meandering. Remote sensing images, DEM data and field investigations are used to assess and interpret controls on these reach transitions. Channel slope and bed sediment size are key determinants of transitions in channel planform. Anastomosing reaches have a relatively high bed slope (0.86‰) and coarser sediment bed material (d 50 = 3.5 mm). In contrast, meandering reaches have a low slope (0.30‰) and fine sediment bed material (d 50 = 0.036 mm). The transition from a meandering to braided pattern is characterized by an increase in channel width-depth ratio, indicating the important role of bank strength (i.e. cohesive versus non-cohesive versus channel boundaries). Interestingly, the braided-meandering and meandering-braided transitions are coincident with variable flow inputs from tributary rivers (Baihe and Heihe rivers respectively). Theoretical analysis of the meandering-braided transition highlights the key control of channel width-depth ratio as a determinant of channel planform.

Choosing the right multiple channel system to minimize transaction costs

This paper proposes that firms can use a transaction cost approach to make multiple channel system design related decisions. The author differentiates between two types of multiple channel systems and hypothesizes that transaction asset specificity, behavioral uncertainty and environmental uncertainty lead manufacturers to adopt either a dual channel system or a multiple independent channel system. Furthermore, the author proposes that when all three transaction cost variables match with the type of multiple channel system used, firms can minimize their transaction costs and eventually increase their channel system performance in terms of contribution to firm profitability. The author tests the hypotheses with survey data collected from 229 firms. The results support that the fit between the type of multiple channel mix and the three transaction-cost theory variables results in lower transaction costs and higher contribution to profit. The author presents theoretical and managerial implications.

True 3D—wide azimuth seismic comes of age onshore as well as offshore

The advantages of recording a well-sampled, wider range of azimuths on seismic surveys are being seen in different geological settings worldwide. The success of wide-azimuth surveys has been well documented for sub-salt illumination in the deep water plays of the Gulf of Mexico. Multi-azimuth surveys have similarly shown improved S/N beneath the Messinian unconformity offshore Egypt. More recently, the benefits of improved sampling (and hence attenuation) of noise by dense, wide-azimuth surveys have been demonstrated onshore Oman. Although the successful marine results have highlighted the benefits of true 3D or wide-azimuth surveys, land surveys have often been recorded with a wide range of azimuths for many years. The step-change occurring onshore is the dramatic increase in the trace density on wide-azimuth surveys. We are learning that one of the reasons that conventional land seismic data have often been viewed as noisy is that coherent energy, particularly near surface events, is grossly under-sampled. Modern land recording techniques such as overlapping vibrator sweeps, single vibrator (point source) recording, multiple vibrator fleets and high channel systems allow us to record data much more efficiently. In turn, these enabling technologies allow us to obtain much improved seismic data quality via greatly increased sampling density. Moreover, recording geometries on this new generation of land supercrews provide trace densities that are many times higher than on marine surveys. The next step for marine wide-azimuth surveys may require a similar step-change in recording density in order to address difficult geologies that cannot be imaged with current recording techniques.

(H2en)2Cu8Sn3S12: a trigonal CuS3-based open-framework sulfide with interesting ion-exchange properties

(H(2)en)(2)Cu(8)Sn(3)S(12) contains a trigonal CuS(3)-based framework into which Sn(4+) ions are incorporated, and exhibits multiple channel systems and interesting ion-exchange properties.

Verification of extension of simultaneous equations method extended to multiple-channel active noise control systems

In this paper, we verify the performance of multiple-channel active noise control systems using the simultaneous equations method. This method has the advantage that it can automatically recover the noise reduction effect degraded by acoustic path changes. The method is hence applied to single-channel systems, and also it is shown that the method results in better performances than the filtered-x algorithm. In this paper, we extend the method to multiple-channel active noise control systems and verify the performance of the extended method by using impulse responses measured with an experimental system. The extended method is applied to a 1-2-2 system, consisting of one noise detection microphone, two loudspeakers and two error microphones, and to a 2-2-2 system including two noise detection microphones, resulting in noise reductions of 14 and 18 dB, respectively. This result demonstrates that the simultaneous equations method well works also for multiple-channel systems.

Modelling of multiple-channel systems of mass service

Article is devoted to modern information technologies. The system of imitating modelling GPSS World (General Purpose Sіmulatіon System World - the world system of imitating general purpose modelling) is considered. Calculation of main parameters of functioning multiple-channel disconnected SMS by an analytical method and with the help of system of imitating modelling GPSSW is carried out and the comparative analysis of results of calculations of these parameters which have been carried out analytical and imitating methods is made

Utilizing reciprocal maximum length sequences within a multichannel context to generate a natural, spatial sounding reverberation.

The development of artificial reverberation has made considerable progress in recent years. Simultaneous advances in knowledge and computational power have allowed for a rapid development and application in the design of virtual room environments. Within such situations, simulating room acoustics is critical for producing a convincing immersive experience. This research explores the application of a multi‐channel loudspeaker setup that can be employed in simulating such an environment. An algorithm to shape and vary the spaciousness within the context of an artificially generated reverberation is implemented. The pseudo‐random properties of reciprocal maximum‐length sequences (R‐MLSs) allow for a deterministic decorrelation between all channels. The use of R‐MLS also provides several advantages over using traditional random noise. This paper will discuss the potential applications in creating virtual spaces and variable acoustic environments using multiple channel systems.

Adding direct or independent channels to multiple channel mix

PurposeThis paper aims to clarify the conditions under which firms can add direct or independent channels to their single channel system and switch to multiple channel systems. Using the transaction cost theory, variables, i.e. specific asset investments, internal uncertainty, and environmental uncertainty, this study seeks to examine how those variables affect firms' decision to adopt a specific multiple channel mix.Design/methodology/approachThe study was conducted within the context of a manufacturer and its multiple channel systems. Using a survey method, primary data were collected from 189 US manufacturers and 98 Taiwanese OEMs. The t‐test and regression analyses were used to test the hypotheses.FindingsThe results indicate that under high‐specific asset investments, high‐environmental uncertainty, and high‐internal uncertainty conditions firms add direct channels and adopt an independent‐direct multiple channel system. On the other hand, under low levels of those variables firms expand their channel system into multiple channels by adopting an independent‐independent multiple channel system.Research limitations/implicationsThe findings provide guidelines to managers regarding the composition of their multiple channel systems. As a limitation, this study uses only three transaction cost variables. Future studies should include other variables that may affect channel design decisions.Originality/valueWhile various studies have analyzed firms' decision to switch to multiple channels by adopting new channels, the nature of those added channels remains under‐researched. This study aims to fill that gap. Also, unlike some other similar studies that only depend on US data, this study tests the hypotheses with the data obtained not only from US manufacturers but also from Taiwanese OEMs

Focus on test and measurement

Focus on test and measurement

Measuring performances of multiple-channel queueing systems with imprecise data: a membership function approach

This paper proposes a mixed integer nonlinear programming (MINLP) approach to measure the system performances of multiple-channel queueing models with imprecise data. The main idea is to transform a multiple-channel queue with imprecise data to a family of conventional crisp multiple-channel queues by applying the α-cut approach in fuzzy theory. On the basis of α-cut representation and the extension principle, two pairs of parametric MINLP are formulated to describe the family of crisp multiple-channel queues, via which the membership functions of the performance measures are derived. To demonstrate the validity of the proposed procedure, a real-world case of multiple-channel fuzzy queue is investigated successfully. Since the performance measures are expressed by membership functions rather than by crisp values, the fuzziness of input information is completed conserved. Thus, the results obtained from the proposed approach can represent the system more accurately, and more information is provided for system design in practice.