Pair Of Ports Research Articles

Bi-directional ROADM with one pair of N x N cyclic-AWGs for over N wavelength channels configuration

Abstract This paper presents a bidirectional optical add-drop multiplexer (BROADM) with permitting white spectral channels input in bidirectional configuration. The filter routing rule of array waveguide grating (AWG) is applied for the wavelength channels (WCs) that need to be added and dropped by using the corresponding tunable fiber Bragg gratings (FBGs). The other WCs pass through output by tuning FBG filter spectra away from the WCs. The bandwidth between two adjacent WCs of each pair of ports in AWG is wider than one channel spacing so that the filter spectra of FBG is tuned to free spectral range (FSR) region to realize the wavelength routing function without interfering other WCs. The WCs can be flexibly handled by installing the corresponding tunable FBG. Therefore, the proposed BROADM is more flexible and has higher transmission capacity in the optical network.

Tighter MIP models for Barge Container Ship Routing

This paper addresses the problem of optimal planning of a liner service for a barge container shipping company. Given estimated weekly demands between pairs of ports, our goal is to determine the subset of ports to be called and the amount of containers to be shipped between each pair of ports, so as to maximize the profit of the shipping company. In order to save possible leasing or storage costs of empty containers at the respective ports, our approach takes into account the repositioning of empty containers. The line has to follow the outbound–inbound principle, starting from the port at the river mouth. We propose a novel integrated approach in which the shipping company can simultaneously optimize the route (along with repositioning of empty containers), the choice of the final port, length of the turnaround time and the size of its fleet. To solve this problem, a new mixed integer programming model is proposed. On the publicly available set of benchmark instances for barge container routing, we demonstrate that this model provides very tight dual bounds and significantly outperforms the existing approaches from the literature for splittable demands.We also show how to further improve this model by projecting out arc variables for modeling the shipping of empty containers. Our numerical study indicates that the latter model improves the computing times for the challenging case of unsplittable demands. We also study the impact of the turnaround time optimization on the total profit of the company.

Container shipping service selection and cargo routing with transshipment limits

We address the tactical planning problem faced by container liner shipping companies to select a set of sailing services from a given pool of candidate services and route available cargo over the chosen services so as to maximize profit. One of the distinctive features of our model is that it incorporates limits on the number of transshipments for each container, a common service requirement in practice. These limits can vary by shipment attributes such as origin and destination, and cargo priority. We propose a new stage-indexed multi-commodity flow model that is based on an augmented network containing links (representing sub-paths) between every pair of ports visited by a candidate service. This sub-path structure, together with our approach of indexing the flow variables by transportation stage, enables the model to accurately capture transshipment costs and enforce transshipment limits. To reduce the computational time to solve this problem, we develop preprocessing steps that exploit network structure to eliminate variables, describe valid inequalities to strengthen the model's linear programming relaxation, and propose an optimization-based heuristic algorithm to generate good initial solutions. We report successful computational results for realistic problem instances from a benchmark suite of liner shipping problems, solved using a standard solver applied to our reduced and strengthened model.

Differential Dielectric Resonator Filters

This paper presents a detailed investigation of the differential bandpass filters with high performance using the popular TE $_{\mathrm {01\delta }}$ -mode ring-shaped dielectric resonator (DR). According to the field distribution of the TE $_{\mathrm {01\delta }}$ mode, the design principle for differentially exciting it is constructed, i.e., a pair of feeding probes should be face-to-face. Under this feeding scheme, it can be found that the resonant modes of the DR cavity can be divided into two kinds of responses, i.e., differential-mode and common-mode responses. Furthermore, the differential feeding scheme is flexible, and then two modified differentially fed structures by changing the positions of differential port pair are introduced to improve the filter selectivity by incorporating an additional transmission zero or to enable the filter to meet the requirement of integration with other differential devices. To validate the proposed idea, several design examples of the differential DR filters are presented, and their simulated and measured results are given.

A scalable multi-stage packet-switch for data center networks

The growing trends of data centers over last decades in- cluding social networking, cloud-based applications, services, and storage technologies enabled many advances to take place in the networking area. Recent changes imply continuous demand for bandwidth to manage the large amount of packetized traffic. Clus- ter switches and routers make the switching fabric in a data cen- ter network (DCN) environment. They are employed to provide in- terconnectivity between elements of the same DC and inter DCs. To handle the constantly variable loads, switches need deliver outstanding throughput along with resiliency and scalability for DCN requirements. Conventional DCN switches adopt crossbars or/and blocks of memories in multistage interconnection architec- tures (commonly 2-tiers or 3-tiers). However, current multistage switches, with their space-memory variants, are either too complex to implement, have poor performance, or not cost effective.We pro- pose a novel and highly scalable multistage switch design based on networks-on-chip (NoC) fabrics for DCNs. In particular, we de- scribe a novel three-stage Clos-network packet-switch fabric with a round robin (RR) packets dispatching scheme where each central stage module is based on a unidirectional NoC (UDN), instead of the conventional single-hop crossbar fabric. The design, referred to as Clos-UDN, overcomes all the shortcomings of conventional mul- tistage architectures. In particular, the Clos-UDN switch: (i) Ob- viates the need for a complex and costly input modules, by means of few, yet simple, input FIFO queues. (ii) Avoids the need for a complex and synchronized scheduling process over a high number of input-output modules and/or port pairs. (iii) Provides speedup, load balancing, and path-diversity thanks to a dynamic dispatching scheme as well as the NoC based fabric nature. Extensive simula- tions are conducted to compare the Clos-UDN switch to some mul- tistage switches. Results show that the Clos-UDN outperforms con- ventional designs under different input traffics, making it highly appealing for ultra-high capacity DC networks.

Containership Traffic Optimization on Feeder Shipping Line

AbstractThis article is devoted to feeder containership traffic optimization on the trunk and feeder shipping lines. The optimization is fulfilled in case of the necessity of laden containers delivery between fixed pairs of ports as well as in case of the requirement not to exceed the vessel's capacity, taking into account her residual value during transition between feeder port lines. The paper takes into account uneven distribution of empty container equipment in ports of line and the solution is suggested considering the estimation of the empty TEU’s number which is subject to reposition.

Strategic maritime container service design in oligopolistic markets

This paper considers the maritime container assignment problem in a market setting with two competing firms. Given a series of known, exogenous demands for service between pairs of ports, each company is free to design liner services connecting a subset of the ports and demand, subject to the size of their fleets and the potential for profit. The model is designed as a three-stage complete information game: in the first stage, the firms simultaneously invest in their fleet; in the second stage, they individually design their services and solve the route assignment problem with respect to the transport demand they expect to serve, given the fleet determined in the first stage; in the final stage, the firms compete in terms of freight rates on each origin–destination movement. The game is solved by backward induction. Numerical solutions are provided to characterize the equilibria of the game.

Design of Broadband Dual-Polarized Patch Antenna With Backed Square Annular Cavity

For obtaining dual-polarization, using a square annular cavity in the ground plane of a broadband microstrip patch antenna, with proximity-coupling as the feeding mechanism, is proposed in this paper. The antenna has four sequentially arranged feed-lines, and each pair of opposite feed-lines in the same direction are excited by antiphase, which provides the high isolation between the two pairs of ports, besides increasing polarization purity. The cavity and the patch act as two radiators, and the square annular shape of the cavity improves their balance, and thus the bandwidth. The design of the antenna, which is based on particle swarm optimization (PSO) algorithm, and the main parameters of the antenna were investigated. To validate the proposed method, a prototype antenna and a feeding balun were fabricated. The measured results show 61% bandwidth (active $\text{VSWR} ), high isolation and good radiation patterns.

FIVE PORTS POWER DIVIDER DESIGNS WITH CONTROLLABLE POWER DIVISION AND SWITCHING CAPABILITIES

Two new 5-port power divider designs capable of controlling the power division ratios between the output ports are proposed. In the first design, the input power is switchable between two pairs of the output ports. This is implemented by terminating the dividers’ two open-ended stubs with varactor diodes. In the second design, the power division is controlled by a single varactor diode that terminates one of the dividers two open-ended stubs. With judicious choice of dc bias voltage, it is possible to realize equal as well as unequal power division ratios between the four output ports. High power division ratios was achieved without the necessity of involving transmission lines with high impedances. It is demonstrated that this design is capable of generating amplitude modulated signals. Simulation and measurement results are presented for the designs to show their power division and matching performance.

Circularly Polarized Antenna Array Technique for MIMO Application

The performance of the proposed antenna design is analyzed and the results are compared with the simulations using IE3D tool. Through the analysis of mutual coupling and correlation between each pairs of antenna ports, it is shown that the antenna achieves good polarization and directivity diversity. A high diversity gain is therefore being achieved. The performance results exhibited by the proposed antenna make it extremely useful for the future generation of wireless broadband communication system.

Compact, high isolation, and dual‐polarized differential dual‐notched UWB‐MIMO slot antenna

ABSTRACTA compact differentially fed ultrawideband‐multiple‐input multiple‐output (UWB‐MIMO) antenna with very high isolation, dual‐polarization, and dual‐notched bands is proposed in this letter. The proposed MIMO antenna consists of two pairs of differential ports which share a common circular radiation slot, making the proposed UWB‐MIMO antenna as compact as one antenna element with the size of 30 × 30 mm2. By arranging two pairs of differential ports orthogonally in the virtual ac ground of each other, the differential isolation can be infinite theoretically and dual‐polarization are obtained. To achieve dual notch‐band, half‐wavelength stubs and slits are introduced. Besides, the radiation characteristic and diversity performance are discussed. Good agreement is achieved between the measured results and simulated results. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2609–2614, 2015

Wideband Differential Bandpass Filters on Multimode Slotline Resonator With Intrinsic Common-Mode Rejection

In this paper, two kinds of wideband differential filters with intrinsic common-mode (CM) rejection are proposed. Both these filters are realized based on the multimode slotline resonators under the dual- and triple-mode resonance, respectively. For Filter 1, the microstrip lines with a pair of differential ports at the two sides are directly tapped on a slotline resonator. For Filter 2, the slotline resonator is connected with two pairs of microstrip open-ended stubs both at top and bottom layers at the beginning. In these two filters, the CM signals are effectively rejected during electromagnetic field conversion. Only the differential-mode performances are left to be focused on. A systematic design method is then presented with simplified circuit models in differential mode, and frequency responses of these models are synthesized and further mapped into physical dimensions. Transformers are used in the mapping procedure and their turn ratios are calculated to find the exact final dimensions or are properly used to realize desired performance with some unattainable impedance values in synthesized simplified models. Finally, two filters are designed, fabricated, and measured to support the design method.

동북아시아 주요 컨테이너항만의 효율성 비교연구

본 연구의 목적은 동북아시아 주요 컨테이너항만간의 상대적 효율성을 분석함으로써, 각 항만의 현재 효율성 수준을 파악하고, 효율적 항만이 되기 위한 주요 전략수립 방안을 제시하고자 하는 것이다, 동북아시아 지역의 주요 16개 항만을 대상으로 개별항만 효율성 및 상대적 효율성을 분석하였으며, DEA기법을 사용했다. DEA모형 중 규모수익불변모형인 CCR모형과 규모수익가변모형인 BCC모형을 통해 항만 효율성을 분석하며, 또한 CCR모형에 의해 평가된 효율성을 BCC모형에 의해 평가된 효율성으로 나눈 비율인 규모의 효율성 측면에서도 효율성을 분석하였다. 이러한 방법의 실증분석을 시행함에 있어서 투입요소로는 선석 수, 안벽 길이, 수심, 부두 총면적, C/C 대수를 이용하고, 산출요소로는 컨테이너 물동량을 이용했다. 연구 결과, 중국의 경우, 대부분의 항만이 효율적으로 나타난 반면, 한국과 일본의 경우 대체적으로 비효율적인 것으로 나타났다. 특히, 부산항과 상해항, 롄윈강항과 인천항, 다롄항과 광양항이 투입요소가 유사하지만 산출요소인 컨테이너 물동량은 큰 차이가 있는 것으로 나타났다. The purpose of this study is to suggest a major strategy to become effective for each port in Northeast Asia by analyzing the relative efficiency of each port to determine the current level of efficiency, efficient harbors plan. Individual port of the major 16 ports in Northeast Asia was analysed targeting efficiency and relative efficiency. In this study, DEA technique was used. Of the DEA model, CCR (constant returns to scale) models and BCC (variable return to scale) model was applied to analyze the efficiency and effectiveness of the port. Then the efficiency measured through CCR model is again compared with the efficiency measured by the BCC model. In this way, the empirical analysis includes the input factors of the operating ports such as the number of berths, wharf, depth, total area of the pier, C / C numbers and output elements includes the container throughput. The results of the study show that most of the ports in China is efficient whereas those in Korea and Japan are relatively inefficient. There are some pairs of ports which has the similar input factors, like Busan port and Shanghai port, Lianyungang port and Incheon port, Dalian port and Gwangyang port, but the container throughput of them has a huge difference.

Strategic Maritime Container Transport Design in Oligopolistic Markets

This paper considers the maritime container assignment problem in a market setting with two competing firms. Given a series of known, exogenous demands for service between pairs of ports, each company is free to design a liner service network serving a subset of the ports and demand, subject to the size of their fleets and the potential for profit. The model is designed as a three-stage complete information game: in the first stage, the firms simultaneously invest in their fleet; in the second stage, they individually design their networks and solve the route assignment problem with respect to the transport demand they expect to serve, given the fleet determined in the first stage; in the final stage, the firms compete in terms of freight rates on each origin-destination movement. The game is solved by backward induction. Numerical solutions are provided to characterize the equilibria of the game.

Impact of Reprocessing Technique on First Level Interconnects of Pb-Free to SnPb Reballed Area Array Flip Chip Devices

The risk of damage caused by reballing SnPb eutectic solder balls onto a commercial off-the-shelf (COTS) active flip chip with a ball grid array (BGA) of SAC305 was studied. The effects of reballing performed by five different reballers were examined and compared. The active flip chip device selected included manufacturer specified resistance between eight (8) differential port pairs. The path resistance between these pins following reballing, as compared to an unreballed device, was used to assess damage accumulation in the package. 2-dimensional x-ray microscopy, acoustic microscopy, and x-ray computer tomography were also used to characterize the effects of reballing. These studies indicated that no measureable damage was incurred by the reballing process, implying that reballed devices should function as well as non-reballed devices in the same application.

Design and Performance of a Cyclic Fault-Tolerant Semiconductor Optical Amplifier Switch Matrix

We propose a cyclic fault-tolerant structure for a semiconductor optical amplifier (SOA) switch matrix in a tree arrangement by connecting the inputs of the switch matrix into a ring with additional SOAs. Upon component failures, the affected requests are rerouted through their neighboring inputs toward the desired outputs. By making use of the existing components while rerouting, the proposed structure achieves an excellent trade-off between the number of additional components, hence size and cost, and fault tolerance. Numerical simulations show that under 210 randomly distributed SOA failures in a 32 × 32 switch matrix, the proposed structure is still able to provide more than 99% connectivity between all input-output port pairs. We also show through simulations that the proposed structure could potentially scale up to large port counts by limiting the length of the rerouted paths. And its fault-tolerance capability improves as the size of the switch matrix increases. Experiments are conducted to verify the feasibility of the proposed structure. Our research provides clues to improve the fault tolerance of some kinds of switch matrices, where rerouting within the switch matrix itself is not possible, such as single-stage matrices.

Scalable and Efficient Diagnosis for 5G Data Center Network Traffic

Data center networks (DCNs) for 5G are expected to support a large number of different bandwidth-hungry applications with exploding data, such as real-time search and data analysis. As a result, significant challenges are imposed to identify the cause of link congestion between any pair of switch ports that may severely damage the overall network performance. Generally, it is expected that the granularity of the flow monitoring to diagnose network congestion in 5G DCNs needs to be down to the flow level on a physical port of a switch in real time with high-estimation accuracy, low-computational complexity, and good scalability. In this paper, motivated by a comprehensive study of a real DCN trace, we propose two sketch-based algorithms, called α-conservative update (CU) and P(d)-CU, based on the existing CU approach. α-CU adds no extra implementation cost to the traditional CU, but successfully trades off the achieved error with time complexity. P(d)-CU fully considers the amount of skew for different types of network services to aggregate traffic statistics of each type of network traffic at an individual, horizontally partitioned sketch. We also introduce a way to produce the real-time moving average of the reported results. By theoretical analysis and sufficient experimental results on a real DCN trace, we extensively evaluate the proposed and existing algorithms on their error performance, recall, space cost, and time complexity.

Experimental Analysis on Oil Film Properties of Plane Port Pair in Axial Piston Machine

To find some rules keeping good lubrication condition for plane port pair in high-performance axial piston pump or motor, especially in the very severe applications, a new test rig was built up to simulate the operational principle of port pair, and to form the lubricating oil film for representative parameter acquisition. This rig is principally characterized by supply pressure up to 30 MPa, accurate control of oil film thickness by separate oil circuit design and electrohydraulic feedback control. The tested oil film working properties was analyzed by comparison with theoretical or simulation references. Experiments show that film balance time and thickness are two key parameters for describing oil film properties, and that working condition factors such as supply pressure, lubricating fluid temperature also notably affects the film thickness and its configuration, but they don’t show equivalent action. Lubrication effects can be valued by the tested frictional torque change of port pair.

Study on the influence of flow force on a large flowrate directional control valve

This paper focuses on analyzing the characteristic of the flow forces acting on a large flowrate directional valve (1200L/min). The flow area of the notches on the spool is calculated and the mathematic model of the spool is presented. The change rule of the total steady flow force is obtained through numerical simulation. The nonlinear response of the spool valve is explained reasonably and the input forces needed to make this valve closing reliability are given out respectively. The results show that the total flow force promotes the spool movement at the beginning but suppresses it after the spool displacement reaches a certain value. Furthermore, the vibration is caused by the dynamic force balance acting on the spool, leading to the large input force to make sure the relative ports closed. It is proposed that each pair of ports of the large flowrate directional control valve should be designed to the same structure to weaken these problems.

Bench scale laboratory tests to analyze non-linear flow in fractured media

Abstract. The knowledge of flow phenomena in fractured rocks is very important for groundwater resources management in hydrogeological engineering. A critical emerging issue for fractured aquifers is the validity of the Darcian-type "local cubic law", which assumes a linear relationship between flow rate and pressure gradient to accurately describe flow patterns. Experimental data obtained under controlled conditions such as in a laboratory increase our understanding of the fundamental physics of fracture flow and allow us to investigate the presence of non-linear flow inside fractures that generates a substantial deviation from Darcy's law. In this study the presence of non-linear flow in a fractured rock formation has been analyzed at bench scale in laboratory tests. The effects of non-linearity in flow have been investigated by analyzing hydraulic tests on an artificially created fractured rock sample of parallelepiped (0.60 × 0.40 × 0.8 m) shape. The volumes of water passing through different paths across the fractured sample for various hydraulic head differences have been measured, and the results of the experiments have been reported as specific flow rate vs. head gradient. The experimental results closely match the Forchheimer equation and describe a strong inertial regime. The results of the test have been interpreted by means of numerical simulations. For each pair of ports, several steady-state simulations have been carried out varying the hydraulic head difference between the inlet and outlet ports. The estimated linear and non-linear Forchheimer coefficients have been correlated to each other and respectively to the tortuosity of the flow paths. A correlation among the linear and non-linear Forchheimer coefficients is evident. Moreover, a tortuosity factor that influences flow dynamics has been determined.