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Presently, the quality assurance of agarwood oil is performed by sensory panels which has significant drawbacks in terms of objectivity and repeatability. In this paper, it is shown how an electronic nose (e-nose) may be successfully utilised for the classification of agarwood oil. Hierarchical Cluster Analysis (HCA) and Principal Component Analysis (PCA), were used to classify different types of oil. The HCA produced a dendrogram showing the separation of e-nose data into three different groups of oils. The PCA scatter plot revealed a distinct separation between the three groups. An Artificial Neural Network (ANN) was used for a better prediction of unknown samples.

Our Sun is surrounded by the Oort Cloud (in radius 0.5 pc) which can be perturbed by various external factors. One of those is the stellar close encounter with our Sun. This kind of perturbation can induce the cometary showers in our Solar System. In this work, we attempt to make numerical simulations to trace the orbit of stars which close encounter with our Sun in the cases of Milky Way’s axisymmetric only and with non-axisymmetric potentials. We have 306 selected solar neighborhood stars from GAIA DR2, LAMOST DR4, and RAVE DR5 which have highly precise kinematics. In this work, we find a few stars that have counter parameter (dm ) less than or equal to 2 pc in both of past and future close encounters with the Sun. We also find a few stars (ID 283, 290, 297, 298) even with dm ≤ 0.5 pc within their errors, for past close encounters at time tm ≥ 0.5 Myr ago. These stars should have perturbed the Oort Cloud’s stability long time ago. Furthermore, we find a few stars (ID 293, 299, 300) with dm ≤ 1 pc within their errors, at tm > 0.6 Myr for future close encounters. Besides that,cadding non-axisymmetric component of Milky Way does not change the results. This suggests that the non-axisymmetric component of Milky Way potential has small effect in perturbing the orbital motion of stars for short timescale. That’s why the values of dm are relatively similar within their errors, for both cases of the Milky Way potential.

Soliton propagation and some related parameter in a photorefractive crystal are considered. This study analyzes the soliton propagation on a photorefractive crystal having both linear and quadratic electro-optical effects through a time-dependent model of nonlinear dynamics equation using the numerical split-step Fourier method. In conducting analysis, we apply various models of ansatz as initial conditions of the optical beam envelope. Based on the studies conducted, ansatz influences the soliton propagation pattern in the photorefractive crystals. Besides, we found ansatz in secant-hyperbolic and Gaussian functions as the most appropriate model for realizing solitons in crystals. Finally, the photorefractive effect supports the evolution of soliton before it achieved a level of stability.

In the pandemic after the occurrence of COVID-19, there are significant changes in economic statistics, this is influenced by economic activity that is not stable compared to before. The price of food staples was also affected by the pandemic, meetings between buyers and traders, usually held in traditional and modern markets, were hampered due to government restrictions on the territory. This causes a decrease in existing transactions in the market, therefore foodstuffs have the possibility of price volatility. Multiple Linear Regression (MLR) algorithm is a method that can overcome predictions with the type of seasonal dataset prediction, therefore the MLR algorithm is implemented to predict food prices, especially in the modern market, based on the predicted prices, then a decision support system is made to make an alternative ranking of food selection accumulation. Based on the available food ingredients there are nutrients contained in these foods, therefore experts are needed to determine the weighting of nutrition in each food ingredient. Simple Additive Weighting (SAW) method is a method that can do weighting and ranking of alternatives. Therefore the SAW method is applied to rank alternative food staples that have nutritional weight and price. Based on the application of MLR, the error level testing concluded that the prediction of the price of food "Rice" has the least error results compared to other foodstuffs with the value of MSE 21261.04, MAE 145.79, RMSE 145.812, MAPE 0.81 while for the best R2 values found at food ingredients "Garlic" with a value of 0.576. Based on testing of the application of SAW, the same results are obtained between manual calculations and calculations provided by the system, so that the accuracy of the system can be ascertained.

DNA research has involved a variety of disciplines across fields, which work complementary and supportive by using the theory, model, and experiment. Physics provides a theoretical basis that can be used for experimentation, as well as developing new physical models. This physical model can explain the nonlinear dynamics of DNA. In this study, we modified Hamiltonian Peyrard-Bishop-Dauxois (PBD) model by adding the influence of the surrounding environment namely thermal bath, in the form of time-dependent thermal friction and stochastic white noise. Both are represented through the Nosé-Hoover-Langevin (NHL) thermostat. Formulations of equation motion are obtained using analytical methods, to be solved using numerical methods. We present the numerical calculations results in phase space images to show chaotic behaviour. Furthermore, we gain an increase in chaotic patterns along with the increase in temperature. In addition, we also obtain the relationship between the distance of the base pair with temperature, especially in the denaturation process.

Benchmarking of the numerical split-step Fourier method in solving a soliton propagation equation in a nonlinear optical medium is considered. This study is carried out by comparing the solutions calculated by numerics with those obtained by analytics. In particular, the soliton propagation equation used as the object of observation is the nonlinear Schrödinger (NLS) equation, which describes optical solitons in optical fiber. By using the split-step Fourier method, we show that the split-step Fourier method is accurate. We also confirm that the nonlinear and dispersion parameters of the optical fiber influence the soliton propagation.

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