Authoritarianism, Democracy, Islamic Movements and Contestations of Islamic Religious Ideas in Indonesia

Since independence, Islamic civil society groups and intellectuals have played a vital role in Indonesian politics. This paper seeks to chart the contestation of Islamic religious ideas in Indonesian politics and society throughout the 20th Century, from the declaration of independence in 1945 up until 2001. This paper discusses the social and political influence of, and relationships between, three major Indonesian Islamic intellectual streams: Modernists, Traditionalists, and neo-Modernists. It describes the intellectual roots of each of these Islamic movements, their relationships with the civil Islamic groups Muhammadiyah and Nahdlatul Ulama (NU), their influence upon Indonesian politics, and their interactions with the state. The paper examines the ways in which mainstream Islamic politics in Indonesia, the world’s largest majority Muslim nation, has been shaped by disagreements between modernists and traditionalists, beginning in the early 1950s. Disagreements resulted in a schism within Masyumi, the dominant Islamic party, that saw the traditionalists affiliated with NU leave to establish a separate NU party. Not only did this prevent Masyumi from coming close to garnering a majority of the votes in the 1955 election, but it also contributed to Masyumi veering into Islamism. This conservative turn coincided with elite contestation to define Indonesia as an Islamic state and was a factor in the party antagonizing President Sukarno to the point that he moved to ban it. The banning of Masyumi came as Sukarno imposed ‘guided democracy’ as a soft-authoritarian alternative to democracy and set in train dynamics that facilitated the emergence of military-backed authoritarianism under Suharto. During the four decades in which democracy was suppressed in Indonesia, Muhammadiyah and Nahdlatul Ulama, and associated NGOs, activists, and intellectuals were the backbones of civil society. They provided critical support for the non-sectarian principles at the heart of the Indonesian constitution, known as Pancasila. This found the strongest and clearest articulation in the neo-Modernist movement that emerged in the 1980s and synthesized key elements of traditionalist Islamic scholarship and Modernist reformism. Neo-Modernism, which was articulated by leading Islamic intellectual Nurcholish Madjid and Nahdlatul Ulama Chairman Abdurrahman Wahid, presents an open, inclusive, progressive understanding of Islam that is affirming of social pluralism, comfortable with modernity, and stresses the need for tolerance and harmony in inter-communal relations. Its articulation by Wahid, who later became president of Indonesia, contributed to Indonesia’s transition from authoritarianism to democracy. The vital contribution of neo-Modernist Islam to democracy and reform in Indonesia serves to refute the notion that Islam is incompatible with democracy and pluralism.

An Adaptive Model Predictive Control System for Virtual Coupling in Metros

Virtual coupling (VC) is an emerging concept and hot research topic in railways, especially for metro systems. Several unit trains in VC drive with a desired minimum distance, and they, as a whole, are regarded as a single train. In this work, a distributed adaptive model predictive control (AMPC) system is proposed to coordinate the driving of each unit train in VC. To obtain the accurate parameters of train dynamics model in a time varying environment, an estimator of the train dynamics model is designed for each AMPC controller. A variable step descent algorithm along the negative gradient direction is adopted for each estimator, which steers the estimated values of the parameters to real ones. Simulations are conducted and the results are compared with both nominal model predictive control system and AMPC system with fixed steps in the literature. Our proposed AMPC system with variable step (AMPCVS) has better performances than other two systems. Results indicate that there is an improvement of the proposed AMPC system with variable steps system when compared with other two existed systems. A running process of VC in a whole inter-station is also simulated here. Experimental results show that the trains track the desired objective well.

The influence of resistant force equations and coupling system on long train dynamics simulations

In the simulation of the longitudinal dynamics of long trains, the modeling of the resistant forces and of the coupling system are two essential aspects. The modeling of the resistant forces directly affects the speed reached by each vehicle as well as the in-train forces. A literature review witnesses different laws for the calculation of both ordinary and accidental resistances. One of the objectives of this paper is to evaluate from the numerical point of view the influence of the resistant forces modeling strategy on the simulation outputs, i.e., on the speeds and in-train forces, by comparing different laws for propulsion and curving resistances. For what concerns the connection between the vehicles of the train, it is well known that the connection system is of utmost importance for the safety and running stability of the train. In this paper, the two existing coupling systems, i.e., the European buffer-hook system and the coupler used outside the European continent are first described, both in terms of operation and modelling techniques, and then they are compared on the same simulation scenario. All the simulations are performed on the first scenario of the International benchmark of the longitudinal train dynamic simulators, using the LTDPoliTO code developed by the railway research team from Politecnico di Torino.

The effect of continuously varying wind speed on high-speed train overturning safety

Changing topography will affect wind speed variations along railway lines in local areas. When the distance from one wind speed abrupt change location to other is narrow, a continuous variation in wind speed will occur. However, few studies have focused on this topic. In this study, a continuous wind speed variation model is developed based on measured wind speed curves, the interval time of continuous wind speed changes, the wind speed amplitude variation, the wind speed change rate and peak wind speed duration on the train dynamics are investigated. The results show that continuous wind speed variations have a significant impact on the overturning safety of trains compared to a single wind speed change. When the interval time between two adjacent wind speed changes is less than 6 s, it is necessary to consider the influence of continuous wind speed variations. In addition, the influence of the wind speed amplitude changes on train overturning safety is much greater than other factors.

Comparisons Between Braking Experiments and Longitudinal Train Dynamics Using Friction Coefficient and Braking Pressure Modeling in a Freight Train

Background: This paper describes the predictions and validation of the pneumatic emergency braking performance of a freight train consisting of a locomotive and 20 wagons, generally operated in Korea. It suggests the possibility of replacing the expensive and time-consuming train running tests with longitudinal train dynamic simulations. Methods: The simulation of longitudinal train dynamics of a freight train uses the time integration method of EN 14531. For reasonable simulation results, the characteristics of the train and brake equipment must be considered. For the train characteristics, specifications provided by the vehicle manufacturer are used. The braking characteristics are analyzed by friction coefficient tests and a braking pressure model. The friction coefficients of a locomotive and wagons are tested with a dynamo test bench and statistically expanded to account for variability. Freight trains should take into account the braking delay time. To reflect this in the simulation, the brake cylinder pressure pattern model uses pressures and exponential empirical equations measured at selective positions in a train of 50 vehicles. The simulation results are validated in comparison with those of the braking tests of a freight train consisting of 1 locomotive and 20 wagons. Results: The results of the longitudinal dynamics simulation show very similar results to the running test results based on the speed profile and braking distance. Conclusion: In particular, the statistical expansion method of the friction coefficient enables robust prediction of the distribution of the braking distance. The simulation can reduce or make up for costly and time-consuming repeated braking tests and reduce the risks that may arise during testing.

Study of Vertical Characteristics with Changes in Prepressure of Rubber Pad Used by High-Speed EMU

Rubber spring plays an important role in improving train performance, so the study of rubber spring is one of the focuses of train dynamics. The vertical characteristic parameters of rubber spring are affected by prepressure significantly, as a result of varying parameters of static stiffness, dynamic stiffness, periodic energy consumption, damping coefficient, and so on. In order to use the theoretical method to calculate the precise static stiffness and predict the dynamic characteristics and to reduce the workload of the rubber spring performance test, this paper takes the annular rubber pad as an example to study with different prepressures. In this paper, the convexity coefficient correction formula (simply called the CCCF) for static stiffness calculation and the dynamic fiducial conversion coefficient (simply called the DFCC) method based on different prepressures are proposed. Through further analysis, the accuracy of CCCF and DFCC is proved both theoretically and experimentally. The results have shown precise prediction of the variation of prepressure on rubber spring parameters by using CCCF and DFCC and can be used as the reference of accurate vertical dynamic-static characteristics of the rubber spring.

Development and validation of a new code for longitudinal train dynamics simulation

Longitudinal train dynamics have a significant impact on both safety and performance of railway systems. Numerical simulation of long heavy haul trains can thus provide essential information for the development of diagnostic and signaling systems as well as coupling elements and braking systems. Long trains are usually modeled by considering only the longitudinal degree of freedom and by adding extra resistant forces to represent the track curvature and gradients. The prediction of in-train forces represents the most critical aspect in modeling the longitudinal dynamics of long trains made up of several vehicles. In fact, coupling elements have non-linear force–deflection characteristics, with different behavior in loading and unloading states, thus featuring a hysteretic loop. Look-up tables storing data from experimental tests are generally used to model these elements; however, other strategies, such as fitting curves and white-box models are witnessed in the literature. Recently, an international benchmarking of longitudinal train dynamics simulator was established in order to compare the output results obtained by different models with the same input data. The research group from Politecnico di Torino performed the simulations using the multibody software Simpack, but computational inefficiencies and numerical divergences occurred. To overcome these issues, a new dedicated in-house code was developed in the MATLAB environment. The paper focuses on the description of this new code and its validation, which was carried out by performing the simulations according to the benchmark inputs and comparing the results with the outputs from the other participants.

Parallel co-simulation of locomotive wheel wear and rolling contact fatigue in a heavy haul train operational environment

Locomotive wheel wear and rolling contact fatigue simulations that consider both train dynamics and detailed traction control systems have not been reported. This paper developed a parallel co-simulation method to link an in-house longitudinal train dynamics simulator to a commercial software package named GENSYS. An advanced longitudinal train dynamics model, a traction control system model and a wheel–rail contact model were then incorporated into the simulation. Three wear calculation models (T-gamma model, USFD model and Archard model) and two rolling contact fatigue calculation models (T-gamma-based rolling contact fatigue model and shakedown-based rolling contact fatigue model) were implemented. A train with the configuration of 1 locomotive +54 wagons +1 locomotive +54 wagons was simulated. This paper shows that the simulation method is successful and can be used for such more detailed locomotive wheel wear and rolling contact fatigue calculations. Wear and rolling contact fatigue calculation results show that the wear numbers that were calculated using the T-gamma wear model and damage indexes that were calculated using the T-gamma-based rolling contact fatigue model were similar between the leading and remote locomotives. However, wear rates that were calculated using the USFD wear model, wear volumes that were calculated using the Archard model and fatigue indexes that were calculated using the shakedown-based rolling contact fatigue model have evident differences between the leading and remote locomotives. Maximum differences in these results were about 12, 18 and 34%, respectively.