Judul: Biaya Eksternal dan Willingness to Accept Masyarakat Akibat Eksternalitas Negatif Pabrik Gula Rafinasi Kabupaten Lampung Selatan
Abstrak: The increase in population effects the demand of sugar. This has led to positive and negative externalities. This research uses qualitative descriptive analysi, loss of earnings method, Contingent Valuation Method (CVM), and multiple linear regression. The example research is purposive sampling. The result shows that the negative externatilies that most imposed on society is degradation of groundwater’s quantity and quality along with degradation of river water quality. This negative externalities caused the society to spend IDR9,176,115,390 of external costs every month. Average WTA value on respondent that owned dried and contaminated well is IDR256,757 per month per patriarch and IDR341,538 per month per patriarch for respondent that owned rice field near the river and cattle which consumed the river water. Several factors that influence respondent’s WTA value for dried and contaminated well: job as farmer, job as breeder, other job, amount of loss, age, income, and water taste, whereas for respondent that owned rice field near the river and cattle: dependent amount, long in stay, job as farmer, job as breeder, amount of loss, age, income, dan water smell.
Keyword: willingness to accept, refined sugar factory, negative externalities, external cost, estimation

Judul: Analisis Eksternalitas Negatif Akibat Pencemaran Limbah Cair Pabrik Gula Tjoekir, Kabupaten Jombang.
Abstrak: Aktivitas industri yang memiliki skala produksi besar akan menghasilkan limbah dalam jumlah yang besar pula. Pabrik Gula Tjoekir didukung oleh aksesibilitas bahan baku berupa tebu yang cukup tinggi di Kabupaten Jombang, memiliki skala produksi yang cukup besar, yaitu 4200 tcd (ton cane per day). Akibatnya limbah cair yang dihasilkan menyebabkan eksternalitas negatif bagi masyarakat di sekitar pabrik. Penelitian ini bertujuan untuk menganalisis eksternalitas negatif yang dirasakan masyarakat, menganalisis biaya eksternal, nilai kompensasi, dan faktor-faktor yang mempengaruhi besarya nilai kompensasi. Penelitian ini menggunakan analisis deskriptif kualitatif, penilaian kerugian, cost of illness, Contingent Valuation Method (CVM), dan regresi linear berganda. Metode pengambilan contoh dengan purposive sampling. Hasil penelitian menunjukkan eksternalitas negatif yang paling dirasakan adalah penurunan kualitas lingkungan dan pencemaran bau. Biaya eksternal rata-rata untuk rumahtangga yang merasakan pencemaran bau Rp26.441 per bulan, rumahtangga yang mengalami pencemaran sumur Rp23.067 per bulan, dan rumahtangga petani dan buruh tani Rp119.508 per bulan. Total nilai kerugian yang ditanggung oleh masyarakat sebesar Rp8.704.445.461 per tahun. Dugaan nilai willingness to accept (WTA) adalah Rp27.286 per bulan per kepala keluarga. Faktor-faktor yang mempengaruhi nilai WTA responden adalah tingkat pendapatan, tingkat pendidikan, usia, jumlah tanggungan, pekerjaan petani, pencemaran bau, dan pencemaran sumur.
Keyword: biaya eksternal, eksternalitas negatif, limbah cair, willingness to accept

Judul: Penggunaan Teorema Homeomorphy 2-Manifold dan Teorema Euler Poincare pada Torus 𝑇�� dan Simplicial Complex 𝐾��
Abstrak: Two dimensional topological spaces are said to be homeomorphic if they have the same topological invariant, where one of topological invariant used is an Euler characteristic. Homeomorphy 2-Manifold’s Theorem and Euler Poincare’s Theorem are used to distinguish two topological spaces. Homeomorphy 2-Manifold’s Theorem uses Euler characteristic to identify two dimensional topological spaces. Euler Poincare’s Theorem is an alternative way to find Euler characteristic with Betti number, which is topological invariant as well. The objective of this paper is to investigate the homeomorphism of torus 𝑇����� and simplicial complex 𝐾�����. Topological space torus and simplicial complex 𝐾����� have the same Euler characteristic, which is two. Based on Homeomorphy 2-Manifold’s Theorem topological space torus 𝑇����� and simplicial complex 𝐾����� is homeomorphic.
Keyword: simplicial, torus, Euler, homeomorphism, topology