Judul: Analysis of Air Quality in Indonesia Using Tensor Decompositon-Based Clustering
Abstrak: Indonesia faces severe challenges in addressing high levels of air pollution. To anticipate and address the effect of air pollution on human health and the environment, all parties need concerted efforts. Grouping regions based on similarities in air quality will help the government tailor policies more effectively. This research aims to conduct a cluster-based analysis of air quality in terms of not only its pollutant compound but also its spatial- and temporal context using tensor decomposition. The cluster elements were then analyzed with similar occurrence patterns to obtain potential factors. Air quality data containing time, region, and air quality parameters are processed to construct a tensor. Air quality parameters being addressed are carbon monoxide (CO), nitrogen dioxide (NO2), sulfur dioxide (SO2), ozone (O3), and particulate matter (PM10 and PM2.5). The data was retrieved from 31 representative monitoring stations across provinces in Indonesia from October 2023 to December 2023. Tensor decomposition with three latent features in each dimension was used for k-medoid clustering using the silhouette and elbow evaluation. Tucker decomposition is used for the general method in tensor decomposition because of its ability to control the decomposition rank. This means regulating the number of latent features or components to be extracted during the decomposition process. The analysis resulted optimal cluster numbers for region, time, and pollutant dimensions. It suggested that four clusters were identified based on region dimension. Meanwhile, in terms of temporal patterns, three clusters resulted. Furthermore, three clusters were identified based on pollutant types. The most concerning region cluster, including Palembang and Pontianak, have PM10 and PM2.5 concentrations above the safe level.
Keyword: air quality, carbon emission, clustering, spatial, temporal

Judul: Analisis Status Kualitas Udara Lima Kota Metropolitan di Indonesia.
Abstrak: The air pollution has become environmental quality indicator that impact to citizen health and affect the air quality in that area. The metropolitan city with rapid population rate and higher living standard as well as prosperity level than in rural area caused the increasing of energy consumption and pollutant emission. The aim of this study was to analyse the air quality status and the correlation between air quality and the condition of metropolitan cities in Indonesia namely Jakarta, Bandung, Medan, Surabaya, and Semarang. Secondly, to determine the factor affecting the air quality in those cities. The data were obtained from the State Ministry of Environment, BPS-Statistics, and the other related institutions which were then processed by SPSS program. Based on the analyzed data, the pollutant concentrations were fluctuated from 2007-2012 in those five cities. The positive correlation was occurred between the amount of vehicles and the concentration of PM10, SO2, and NO2, between the population and the concentration of SO2 and NO2, also between energy consumption and SO2. The negative correlation was occurred between the green open area with CO and NO2. Therefore, the factors that affect the air quality in metropolitan cities in Indonesia are population, vehicles, and green open area. Moreover, industrial estate and meteorological factor are allegedly to affect air quality in those cities.
Keyword: air quality, metropolitan city, correlation, Indonesia

Judul: Kawin Berulang Pada sapi, Kausa Kuman Aspesifik Dan Pengobatannya
Abstrak: Kawin berulang pada sapi betina adalah merupakan bantuk atau geja1a inferti1itas, dimana sapi-sapi yang menderita kawin beru1ang tersebut mempunyai siklus berahi yang normal atau hampir normal dan sudah dikawinkan dua ka1i atau 1ebih dengan pejantan atau semen pejantan fertil, tapi tetap belum bisa bunting. Pemeriksaan klinis terhadap sapi tersebut tidak memberikan gambaran tertentu yang dapat menerangkan kegaga1an konsepsi yang dialami (Roberts, 1971).
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