Background: Understanding the pattern of COVID-19 infection progression is critical for health policymakers. Reaching the exponential peak of cases, flattening the curve, and treating all of the active cases are the keys to success in reducing outbreak transmission. The objective of this study was to determine the most effective model for predicting the peak of COVID-19 in Indonesia, using a deterministic model. Methods: The SEI2RS model considers five strategies for control, namely: large-scale social restriction (u 1), contact tracing (u 2), mass testing (u 3), case detection and treatment (u 4), and the wearing of face masks (u 5). Three scenarios were developed, each differentiated by the controls. The model used April 10, 2020, and December 31, 2020, as the initial and final times. Results: The simulation results indicated that the peak of COVID-19 cases for scenarios 1, 2, and 3 occur on the 59th day with 33,151 cases, on the 38th day with 37,908 cases, and on the 40th day with 39,305 cases. For all of the scenarios, the decline phase shows a slow downward slope and about 8000 cases of COVID-19 still active by the end of 2020. Conclusion: The study concludes that scenario 2, which consists of large-scale social restriction (u 1), contact tracing (u 2), case detection and treatment (u 4), and the wearing of face masks (u 5), is the most rational scenario to control COVID-19 spreading in Indonesia.

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Malacca Strait (MS) has an important role and potential for many countries. It is a major transportation route for oil and commodities across continents. In addition, various activities such as shipping, fishing, aquaculture, oil drilling, and energy are also carried out in MS. Tides strongly affect the MS environment so that it becomes a major parameter in MS management. This paper is the first study, which presents MS tidal hydrodynamics based on a baroclinic and nonhydrostatic approach. Tidal hydrodynamics in MS and the surrounding waters were assessed using tidal forces, temperature, salinity, and density. This study analyzes the amplitude, phase, current ellipses, and semi-major axis of the tides. These variables are obtained from the simulation results of the three-dimensional numerical models of M2 tides and combined tides (M2, S2, N2, K1, and O1) with nonhydrostatic models. Then the results obtained are verified by observation data. Amplitude and phase of the tidal wave in MS originate from two directions, namely the northern part of MS (Andaman Sea) and the South China Sea (SCS). Tides from the north of MS propagate into the MS, while tides from the SCS travel to Singapore Waters (SW) and the south of MS. This causes a complex residual flow in SW and shoaling in the middle of MS. Shoaling in the middle of MS is characterized by a large amplitude and semi-major, as in B. Siapiapi. The results of this analysis show that tidal waves are dominated by semidiurnal types rather than diurnal types. The M2 current ellipse has dominantly anticlockwise rotation along the west of the MS, while along the east of MS, it has generally a clockwise rotation.

The use of solar energy using solar panels began to be encouraged. Solar panels utilize solar radiation and convert it into clean and renewable energy. The problems of the accuracy of the panel facing right towards radiation are a challenge in the development of a driving system. Solar panels have limited motion, which is a maximum of phi, so that wind disturbances are very dangerous for motor drives and solar panels. This paper aims to eliminate wind disturbances in solar panel drive systems. The fuzzy logic control is used to determine the amount of power given to the driving motor to direct the panel towards solar radiation. Inputs and outputs of fuzzy controllers are arranged by dividing into each of the five members. Simulation results show that the position error of solar panels without wind disturbances reaches 0.3325° in zonal and 0.5210° in meridional. By using wind disturbances, this system managed to maintain errors smaller than 0.4285° in zonal and 0.6116° in meridional. After modifying the rule base and membership function, systems show decreasing of error half of recent trial.

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This study aims to observe tidal sea behavior in Bay of Sabang by using a two-dimensional hydrodynamic model. The research domain was obtained from SRTM15, which had been interpolated so that it has a spatial resolution Δx = Δy = 0.1 minutes (185 meters). As a generator force, the open boundaries model is given five main tidal components (M2, S2, K1, N2, O1) obtained from TPXO 7.2 data. The model is simulated for 31 days with time step based on CFL condition criteria. Our model verification is quite good when compared with TMD prediction data (r = 0.9996). It shows that our model can be used for tidal hydrodynamics studies in Bay of Sabang. The results show that tides in Bay of Sabang are predominantly mixed prevailing semi-diurnal (F = 0.857). The speed of tidal currents in Bay of Sabang is quite small both for spring and neap tides. The difference in velocity between spring and neap tides reaches 0.6 cm/s.

An area generally has a different character from other regions, including the limited resources that exist in the area. Therefore, it is necessary to strive to encourage human resources through various interactions, and one of the efforts made is the interaction of organizational capacity in the field of innovation. The purpose of this study is to analyze and evaluate the process of organizational interaction in the field of community innovation in Magelang City, Central Java Province, Indonesia. Secondary data sources from the Magelang City Research and Development Agency were 322 innovations from 2004 to 2019, while the primary data came from structured interviews with ten innovators. The findings of the analysis are presented with a qualitative description to evaluate the interaction of innovations in the context of local government organizations. The sampling technique in the study uses accidental sampling. The analysis tool uses participatory exploration that focuses on the government's efforts as an internal organization in encouraging the community as an external organization through the interaction of innovation. The findings of this study are the formation of informal organizations in the community through the interaction of innovations carried out through internal organizational mechanisms. The finding in this study is that the organization's internal interactions in innovation are proven to be beneficial for the community which encourages the growth of community innovation, increases people's income, and contributes to increasing Magelang City's Regional Original Income.

The Makassar Strait (MS) connects the Pacific Ocean and Indonesia Waters via the Indonesia throughflow system. The flow varies because MS is also influenced by the monsoon. To determine the monsoon effect, we applied the two-dimensional numerical model with 6 hourly wind data. It was used to predict the MS current circulation during February, April, August, and October. According to recent studies, the results showed a good verification. The currents in the MS were dominated from the north of MS. The currents moved to the south of MS but sometimes deflected to the north. The currents were stronger during August and weaker during February. In August, the current from the north of MS moved to the south of MS, and it was partly deflected toward the north around Sulawesi Island. There was also the current from the south of MS directed toward the north. While in February, the current around Kalimantan Island was always to the south of MS. Based on the results, the MS currents were dominated by the currents from the north of MS or the Pacific Ocean.