Judul: Water quality and land use around Sunter 1 Lake, DKI Jakarta
Abstrak: Meningkatnya jumlah penduduk di DKI Jakarta berpotensi menyebabkan terjadinya perubahan tata guna lahan yang berpengaruh terhadap peningkatan jumlah limbah yang dihasilkan di badan air. Salah satu badan air yang terancam tercemar oleh limbah dari aktivitas manusia adalah Danau Sunter 1. Penelitian ini bertujuan menganalisis status kualitas air dan tata guna lahan di sekitar Danau 1, DKI Jakarta. Penelitian ini menggunakan data sekunder kualitas air Danau Sunter 1 tahun 2019, 2021, dan 2022. Penelitian dilakukan selama dua periode dengan tiga titik pengambilan sampel. Status kualitas air Danau Sunter 1 dianalisis menggunakan Indeks Pencemaran (IP), sedangkan data tata guna lahan dianalisis menggunakan software Google Earth Engine (GEE) dan ArcGIS. Kualitas Air Danau Sunter 1 tergolong dalam kategori cemar ringan, cemar sedang dan cemar berat. Lahan terbangun merupakan penggunaan lahan yang memiliki luasan paling mendominasi, sedangkan semak merupakan penggunaan lahan dengan luasan terendah. Tingginya lahan terbangun dikarenakan peningkatan populasi jumlah penduduk di Jakarta Utara yang menyebabkan adanya konversi menjadi lahan terbangun., The increasing population in DKI Jakarta has the potential to cause land use changes that affect the increase in the amount of waste generated in water bodies. This study aims to analyze the status of water quality and land use around Sunter 1 Lake, DKI Jakarta. This study used secondary data on the water quality of Lake Sunter 1 in 2019, 2021, and 2022. The research was conducted over two periods with three sampling points. The water quality status of Sunter 1 Lake was analyzed using the Pollution Index (IP), while land use data was analyzed using Google Earth Engine (GEE) and ArcGIS software. The water quality of Sunter 1 Lake is categorized as lightly polluted, moderately polluted and heavily polluted. Built-up land is the land use that has the most dominating area, while shrubs are the land use with the lowest area. The high amount of built-up land is due to the increase in population in North Jakarta, which has led to conversion to built-up land.
Keyword: water quality, Sunter 1 Lake, land use

Judul: The Relationship between Land Use Change and Water Quality in Pluit Reservoir, DKI Jakarta
Abstrak: Meningkatnya penduduk dan penggunaan lahan di DKI Jakarta berpengaruh terhadap meningkatnya jumlah limbah yang dihasilkan. Limbah tersebut jika masuk ke badan air dapat mencemari perairan. Salah satu badan air yang berpotensi terkena dampak masukan limbah dari kegiatan manusia ialah Waduk Pluit. Penelitian ini bertujuan menganalisis keterkaitan antara perubahan penggunaan lahan dengan kualitas air di Waduk Pluit. Penelitian dilaksanakan selama dua periode (April dan September) dengan empat titik stasiun pengambilan sampel. Penelitian ini juga menggunakan data sekunder kualitas air Waduk Pluit tahun 2018 dan 2019. Lahan terbangun merupakan penggunaan lahan yang mendominasi, sedangkan lahan terbuka merupakan penggunaan lahan dengan luasan terendah. Penggunaan lahan untuk badan air memiliki keterkaitan secara signifikan dan berkorelasi negatif dengan TDS, sedangkan semak berkorelasi positif dengan TDS. Daerah bervegetasi dan lahan terbuka memiliki keterkaitan secara signifikan dan berkorelasi positif dengan DO, namun berkorelasi negatif dengan fecal coliform dan total coliform. Penggunaan lahan untuk lahan terbangun memiliki hubungan sangat kuat dan berkorelasi negatif dengan DO, namun berkorelasi positif dengan fecal coliform dan total coliform., The increasing population and land use in DKI Jakarta affect the increase in the amount of waste produced. If the waste enters water bodies, it can pollute the water. One of the water bodies potentially affected by the input of waste from human activities is the Pluit Reservoir. This study aims to analyze the relationship between land use change and water quality in the Pluit Reservoir. The study was carried out in two periods (April and September) with four sampling stations. This study also uses secondary data, namely the water quality of the Pluit Reservoir in 2018 and 2019. Built-up land is the dominant land use, while open land is the land use with the lowest area. Land use for water bodies has a significant and negative correlation with TDS, while shrubs have a positive correlation with TDS. Vegetated areas and open land are significantly and positively correlated with DO but negatively correlated with fecal coliform and total coliform. Land use for built-up land has a very strong relationship and has a negative correlation with DO but a positive correlation with fecal coliform and total coliform.
Keyword: land use, Pluit Reservoir, water quality

Judul: Penentuan Nilai Eigen dan Vektor Eigen dari Matriks Tridiagonal 2-Toeplitz dengan Pendekatan Polinomial Chebyshev
Abstrak: The eigenvalues and eigenvectors of a matrix can be determined by finding its characteristic polynomials. The characteristic polynomials of a tridiagonal 2-Toeplitz matrix is shown to be closely connected to polynomials which satisfy the Chebyshev recurrence relationship. If the order of the matrix is odd, then the eigenvalues are found explicitly in terms of the Chebyshev zeros and the eigenvectors are found in terms of the polynomials satisfying the recurrence relationship. For even ordered matrices, the situation is more complicated. The problem in these cases is that although the Chebyshev recurrence formula is still applied, its initial values are not generating Chebyshev polynomials
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