Effectiveness evaluation of aerial reconnaissance in battalion force protection operation using the constructive simulation

The paper sets out the results of an experiment carried out using MASA SWORD simulator to verify the use of the unmanned aerial vehicle (UAV) reconnaissance model during battalion force protection activities. The authors focus particularly on the first phase of the battle—enemy approaching and early reconnaissance. The reconnaissance was planned using the UAV reconnaissance model which is part of the Tactical Decision Support System (TDSS). The aim of the experiment is to verify the possibilities of using the UAV reconnaissance model for battalion-size unit force protection and to compare this model with ordinarily used tactical procedures. The experiment proves the hypothesis defined in the introduction and quantifies some defined variables. Based on the result of the experiment, it is possible to state that UAV reconnaissance has significant impact on the effectiveness of the military mission. Moreover, the simulation environment opens a wide range of possibilities for future research including multiple simulations of the scenario, comparison of achieved results in dependence on the set conditions and variable settings, tailoring tactics for the scenario at hand, and so on.

Mathematical Relationships between Motoneuron Properties Derived by Empirical Data Analysis: Size Determines All Motoneuron Properties

Our understanding of the behaviour of motoneurons (MNs) in mammals partly relies on our knowledge of the relationships between MN membrane properties, such as MN size, resistance, rheobase, capacitance, time constant, axonal conduction velocity and afterhyperpolarization period. Based on scattered but converging evidence, current experimental studies and review papers qualitatively assumed that some of these MN properties are related. Here, we reprocessed the data from 27 experimental studies in cat and rat MN preparations to empirically demonstrate that all experimentally measured MN properties are associated to MN size. Moreover, we expanded this finding by deriving mathematical relationships between each pair of MN properties. These relationships were validated against independent experimental results not used to derive them. The obtained relationships support the classic description of a MN as a membrane equivalent electrical circuit and describe for the first time the association between MN size and MN membrane capacitance and time constant. The obtained relations indicate that motor units are recruited in order of increasing MN size, muscle unit size, MN rheobase, unit force recruitment thresholds and tetanic forces, but underlines that MN size and recruitment order may not be related to motor unit type.

Characteristics of the Electrophysiological Properties of Neuromuscular Motor Units and Its Adaptive Strategy Response in Lower Extremity Muscles for Seniors with Pre-Sarcopenia: A Preliminary Study

Older adults with sarcopenia, which is an aging-related phenomenon of muscle mass loss, usually suffer from decreases in both strength and functional performance. However, the causality between function loss and physiological changes is unclear. This study aimed to explore the motor unit characteristics of the neurological factors between normal subjects and those with sarcopenia. Five risk-sarcopenia (age: 66.20 ± 4.44), five healthy (age: 69.00 ± 2.35), and twelve young (age: 21.33 ± 1.15) participants were selected. Each participant performed knee extension exercises at a 50% level of maximal voluntary isometric contraction. Next, electromyogram (EMG) signals were collected, and information on each parameter—e.g., motor unit number, recruitment threshold, the slope of the mean firing rate to recruitment threshold, y-intercept, firing rate per unit force, and mean motor unit firing rate (MFR)—was extracted to analyze muscle fiber discrimination (MFD). Meanwhile, force variance was used to observe the stability between two muscle groups. The results suggested that there was no difference between the three groups for motor unit number, recruitment threshold, y-intercept, mean firing rate, and motor unit discrimination (p > 0.05). However, the slope of MFR and firing rate per unit force in the risk-sarcopenia group were significantly higher than in the young group (p < 0.05). Regarding muscle performance, the force variance in the non-sarcopenia group was significantly higher than the young group (p < 0.05), while the risk-sarcopenia group showed a higher trend than the young group. This study demonstrated some neuromuscular characters between sarcopenia and healthy elderly and young people when performing the same level of leg exercise tasks. This difference may provide some hints for discovering aging-related strength and function loss. Future studies should consider combining the in vivo measurement of muscle fiber type to clarify whether this EMG difference is related to the loss of muscle strength or mass before recruiting symptomatic elderly participants for further investigation.

Considerations on the human Achilles tendon moment arm for in vivo triceps surae muscle–tendon unit force estimates

Moment arm-angle functions (MA-a-functions) are commonly used to estimate in vivo muscle forces in humans. However, different MA-a-functions might not only influence the magnitude of the estimated muscle forces but also change the shape of the muscle’s estimated force-angle relationship (F-a-r). Therefore, we investigated the influence of different literature based Achilles tendon MA-a-functions on the triceps surae muscle–tendon unit F-a-r. The individual in vivo triceps torque–angle relationship was determined in 14 participants performing maximum voluntary fixed-end plantarflexion contractions from 18.3° ± 3.2° plantarflexion to 24.2° ± 5.1° dorsiflexion on a dynamometer. The resulting F-a-r were calculated using 15 literature-based in vivo Achilles tendon MA-a-functions. MA-a-functions affected the F-a-r shape and magnitude of estimated peak active triceps muscle–tendon unit force. Depending on the MA-a-function used, the triceps was solely operating on the ascending limb (n = 2), on the ascending limb and plateau region (n = 12), or on the ascending limb, plateau region and descending limb of the F-a-r (n = 1). According to our findings, the estimated triceps muscle–tendon unit forces and the shape of the F-a-r are highly dependent on the MA-a-function used. As these functions are affected by many variables, we recommend using individual Achilles tendon MA-a-functions, ideally accounting for contraction intensity-related changes in moment arm magnitude.

PERAN PEMERINTAH KOTA DEPOK DALAM PENANGANAN MANTAN ANGGOTA GAFATAR

One of the the policy directions of the government in order to strengthen harmonious life of religious communities is to protect religious minority groups and religion-based trauma healing. This qualitative descriptive-designed research is an evaluative study to the local unit force of Depok City which has authority to deal with ex-Gavatar members and other citizens who were recorded as ex-Gavatar members. The research discovers that in dealing with ex-Gavatar members, the government of Depok City is still limited in picking up, data collecting, sheltering, psychological consulting, and returning them home. In addition, the post-returning action is limited in the observation and supervision of state-national insight. There has not been a policy to provide personal training and mentoring to the ex-Gavatar members. Some of their civil rights are still ignored. This includes services of population administration, education, and return on their assets in Kalimantan. The obstacle factor in dealing with ex-Gavatar members is mainly in the inflexible budget when facing social dynamics, especially when dealing with victims of social conflicts.

A Simplified Method to Invert Slow Slip Events: Examples for the 2002, 2006 and 2014 events in Guerrero, Mexico

An efficient method to obtain a simple model of the slip distribution on a fault plane was developed from estimates of static offsets from continuous GPS measurements. Transfer functions were computed for the displacement due to a unit force on a fault plane (with a predetermined geometry, subdivided in a den-se grid of subfaults) for all combinations of stations and subfaults, considering a layered media. The forward problem is built as a linear combination of elliptical slip-patches over the fault plane and the transfer functions between each patch and each station. To test the method, the 2002, 2006 and 2014 slow slip events (SSE) were modeled in Guerrero, Mexico, assuming that slip occurred along the subduction interface between the Cocos and North America plates. This subduction fault was modeled as two adjacent planes, both striking 289° for 600 km approximately parallel to the Middle America trench and with a width of 120 km (240 km total width). The shallower plane starts at the trench and dips 14° and the deeper plane is sub-horizontal (2° dip). The merged fault plane is segmented in 120x48, 5x5 km2 subfaults. A pre-calculated set of transfer functions is kept for future slow slip events, so that these only need to be computed for new GPS stations. A strong agreement between observations and synthetic data was found for all analyzed events, and the results are consistent with those reported by previous studies.

Elastodynamic image forces on screw dislocations in the presence of phase boundaries

The elastodynamic image forces acting on straight screw dislocations in the presence of planar phase boundaries are derived. Two separate dislocations are studied: (i) the injected, non-moving screw dislocation and (ii) the injected (or pre-existing), generally non-uniformly moving screw dislocation. The image forces are derived for both the case of a rigid surface and of a planar interface between two homogeneous, isotropic phases. The case of a rigid interface is shown to be solvable employing Head's image dislocation construction. The case of the elastodynamic image force due to an interface is solved by deriving the reflected wave's contribution to the global solution across the interface. This entails obtaining the fundamental solution (Green's function) for a point unit force via Cagniard's method, and then applying the convolution theorem for a screw dislocation modelled as a force distribution. Complete, explicit formulae are provided when available. It is shown that the elastodynamic image forces are generally affected by retardation effects, and that those acting on the moving dislocations display a dynamic magnification that exceed the attraction (or repulsion) predicted in classical elastostatic calculations.

NUMERICAL MODELING OF BREAKING SOLITARY WAVE RUN UP IN SURF ZONE USING INCOMPRESSIBLE SMOOTHED PARTICLE HYDRODINAMICS (ISPH)

This paper presents a numerical model for simulating wave run-up on rough sloping surfaces. Incompressible smoothed particle hydrodynamics (ISPH) has been utilized, which is capable of efficient tracking of free surface deformation in a Lagrangian coordinate system. Many of the existing models have focused on inviscid wave run-up on a smooth surface, but few numerical models and especially experimental studies have investigated the effect of beach roughness on the run up. In the present study two methods have been deployed to study the effect of roughness on wave run up. In the first method, the mass unit force, which is a coefficient of the fluid viscosity, and is dependent on the roughness of the solid boundary, has been used. In the second method, mass unit force obtained from the wall functions was utilized to enforce the friction on the particles near the boundaries. The comparisons of the numerical simulations with the analytical solutions and experimental data confirmed the capability of the model in simulating wave propagation and wave breaking. It was also concluded that the effect of roughness on wave run up depends on both the roughness itself and the beach slope. The results also indicated small roughness effect on waves running up over steep slopes.