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The two-layer network model offers us a new viewpoint to observe the traffic dynamics of multilayer network systems. An efficient coupling mechanism is of great importance for alleviating the traffic congestion on two-layer networks. In order to reduce the network congestion and improve network transmission performance, the coupling mechanism between two layers of network and three coupling methods, which are random coupling, disassortative coupling and assortative coupling, are studied based on degree correlation. The packet transmission process is analyzed with both the shortest path routing strategy and degree-based weight routing strategy. The influences of the coupling mode and its corresponding routing strategy on the traffic capacity of the two-layer network are studied. In this paper, two scale-free networks are used to construct the two-layer network for simulation experiments. The network scale is in a range from 200 to 2400 with the value of average degree being 8. We focus on the traffic dynamics of two-layer network, and analyze the relationship between the traffic capacity and the three coupling modes, which are random coupling, disassortative coupling and assortative coupling, under the constraints of the shortest path routing strategy and the weight-based routing strategy. According to the characteristics of the coupling connection between the two layers of network, the best coupling method which is suitable for a certain routing strategy should be investigated. The suitable coupling connection between the two layers can effectively increase the traffic capacity. Both numerical result and analytical result show that the packet generation rate, average transmission time, and average throughput can be obviously improved under the shortest path routing strategy with the disassortative coupling method. When the degree-based static weight routing strategy is used, the traffic performance parameters such as packet generation rate, average transmission time, and average throughput can reach the optimal values with the assortative coupling method. It makes the traffic flow uniform that the routing strategy is chosen with the most suitable coupling method on the two-layer network, and the network traffic capacity may be effectively enhanced. More generally, the results indicate that the coupling modes can give rise to traffic behavior that relies subtly on the routing strategy on the two-layer network. Our work may shed some light on the design and optimization of some real traffic or communication networks.

The generally adopted worldwide target is to keep the increase in the global mean temperature lower than 2 °C by 2100, which is comparable with that of the preindustrial era. It is feasible for China to realize an emission pathway that is consistent with this target, however, we need to understand the roadmap to do so. In this paper, the results of a modeling study by the Integrated Policy Assessment Model for China (IPAC) concerning the investment required to realize the 2 °C scenario by examining the penetration of low-carbon technologies including energy supply and energy efficiency improvement in end-use sectors is presented. It is found that the investment required in the energy supply sector to realize the 2 °C scenario could reach CN¥1.2 trillion by 2020, CN¥1.0 trillion by 2030, and CN¥1.4 trillion by 2050. The investment needed for energy saving could reach CN¥1.6 trillion by 2020, CN¥1.8 trillion by 2030, and CN¥1.5 trillion by 2050, which represents the additional investment as compared with the use of old technologies. If the investment required both in the energy supply sector and in energy saving in end-use sectors is considered, the total investment is estimated to be CN¥2.8 trillion by 2020, CN¥2.8 trillion by 2030, and CN¥2.9 trillion by 2050. These investments account for 2.5% of Chinas total GDP in 2020, 1.3% in 2030, and 0.6% by 2050, which represents quite a small investment percentage to realize the goal of low-carbon development.

OBJECTIVE: To describe the technique and analyze the outcomes of joint‐preserving surgical treatments which included anatomical reconstruction or alignment correction for talar malunions or nonunions, and avoid development of degenerative changes in the adjacent joints. METHODS: Eight patients who had painful talar malunions or nonunions treated between 2009 and 2015 were included in this retrospective study. The mean age of the patients was 35.6 years, with patients aged from 18 to 58 years. Two patients had talar neck fractures and six had talar body fractures. According to a classification of post‐traumatic talar deformities, five patients were classified as type I (malunion and/or residual joint displacement), two as type II (nonunion with displacement), and one as type III (malunion with partial avascular necrosis [AVN]). Of these patients, six cases were treated with an osteotomy through the malunited fracture or removal of the pseudarthrosis, and two cases were corrected by supramalleolar or calcaneal osteotomies owing to complete disappearance of the former fracture lines. The follow‐up evaluation methods included the 36‐Item Short Form Health Survey (SF‐36) score, the American Orthopaedic Foot and Ankle Society (AOFAS) score, range of motion (ROM), and radiological analysis. The differences between postoperative scores and preoperative scores were evaluated statistically with the paired Student's t‐test. Significance was assumed at P < 0.05. RESULTS: The mean follow‐up time was 25.6 months. No wound healing problems or infections were observed. Solid union was obtained without redislocation in all cases, and with no signs of development or progression of AVN. At a mean of 25.6 months (range, 16–36 months) after reconstruction, all patients were satisfied with the result. The mean AOFAS score increased from 30.0 ± 7.0 pre‐operatively to 86.5 ± 7.8 post‐operatively (P < 0.001), the mean SF‐36 score increased from 38.8 ± 4.1 to 81.4 ± 7.7 (P < 0.001), and the average ROM (tibiotalar joint) increased from 40.5° ± 8.7° to 43.9° ± 7.2° (P < 0.05). DISCUSSION: Joint‐preserving procedures for talar malunions or nonunions can bring about satisfactory outcomes, and the appropriate procedure should be adopted according to different types of post‐traumatic deformities.

Theidentification and modeling theory of nonlinear systems has always been challengingto researchers. Fuzzy system due to its languagedescriptive way similar to human brain and deal with qualitative informationintelligently proves better choice for nonlinear system modeling over last fewdecades. The fuzzy system theory itself also has nonlinear characteristics thereforewhen establishing the fuzzy model of nonlinear system; it should be able towell describe the nonlinear characteristics. Takagi-Sugeno (TS) fuzzy systemsare not only suitable for modeling the nonlinear system due to combination ofthe good performance with the simple linear expressions, but also useful todesign the fuzzy controller. This paper proposed a new optimization algorithm namedas Enhanced Gradient Search (EGS) for identification of nonlinear system basedon TS fuzzy system. In proposed EGS, parameters of membership functions aretrained adaptively so as to calculate the gradient of cost function which isnecessary for minimizing the error. Using gradient information of costfunction, EGS applies in an innovative way such that it keeps and updates thebest search results at every training step during the optimization process. Theapplicability of EGS for TS fuzzy model shows splendid performance especially inmodeling of nonlinear system.

Dynamics of miniature unmanned helicopter are considered nonlinear and mutually coupled; therefore designing of a stable control becomes a big challenge for researchers. This paper addresses this issue by proposing a hybrid control methodology using both traditional and intelligent control. A 3DoF model helicopter system is used as a controlled platform. This hybrid control used PID as a traditional and fuzzy as an intelligent control so as to take the full advantage of advanced control theory. Proposed hybrid control is evaluated against the fuzzy and PID control through intensive simulation. Results verified that the proposed control has an excellent performance in static as well as dynamic environment as compared to individual PID and fuzzy control. DOI : http://dx.doi.org/10.11591/telkomnika.v12i5.5091

This paper presents system identification method for small unmanned helicopter based on Takagi Sugeno fuzzy models under hover. Firstly,the nonlinear discrete model of small unmanned helicopter with unknown parametersis determined by Takagi Sugeno system. Secondly, derivative based gradientmethod is used to identify unknown parameters of TS fuzzy model because in gradientadaptation, fuzzy system is not supposed to be linear in the parameters, so allfuzzy sets for input and output could be adjusted. The proposed method showedits effectiveness in terms of data matching obtained by the X-Plane©flight simulator. Obtained simulation results show high accuracy of themodeling method and better justification for real time applicability of theapproach DOI : http://dx.doi.org/10.11591/telkomnika.v12i1.3577