Judul: Monitoring System for Environmental and Water Quality at Mangrove Crab Hatchery in Brebes Regency, Central Java
Abstrak: Kepiting bakau merupakan salah satu komoditas perikanan yang memiliki potensi sebagai sumber kehidupan masyarakat, terutama bagi nelayan skala kecil. Ekosistem mangrove mempunyai peran penting sebagai habitat utama kepiting bakau (Scylla Sp). Kepiting bakau (Syclla Sp.) sering disebut sebagai kepiting lumpur, karena menggali dan menghuni liang di hutan bakau dan perairan intertidal dangkal yang lunak. Penyebaran Kepiting Bakau hampir di seluruh Kawasan pesisir Indonesia, yang memiliki ekosistem mangrove. Dalam proses pembudidayaan kepiting bakau, diperlukan beberapa parameter agar dapat mengetahui kondisi habitat kepiting secara langsung. Penelitian bertujuan menampilkan data yang didapatkan menggunakan rancang bangun sistem monitoring pada hatchery kepiting bakau di Brebes. Rancang bangun sistem monitoring pada hatchery kepiting bakau dinilai berhasil menampilkan data parameter lingkungan menggunakan perangkat lunak Blynk. Terdapat empat parameter yang ditampilkan, yaitu kelembaban udara, suhu udara, suhu air, dan jarak. Melalui analisis statistik deskriptif pada data bulan November didapatkan nilai kelembaban udara sebesar 65-98%, suhu udara sebesar 24-31°C, suhu air sebesar 27-34°C, dan jarak antara posisi sensor dengan permukaan air laut sebesar 17-69 cm. Berdasarkan data tersebut maka kualitas perairan di hatchery kepiting bakau, Kabupaten Brebes dinilai cocok untuk habitat kepiting bakau dan budidaya kepiting bakau., Mangrove crabs are a significant fishery commodity with the potential to support the livelihoods of local communities, particularly small-scale fishermen. Mangrove ecosystems play a crucial role as the primary habitat for mangrove crabs (Scylla spp.). Mangrove crabs (Scylla spp.) are often referred to as mud crabs because they burrow and inhabit burrows in mangrove forests and soft, shallow intertidal waters. The distribution of mangrove crabs spans almost all coastal areas of Indonesia with mangrove ecosystems. In the cultivation of mangrove crabs, several parameters are needed to directly assess the habitat conditions for the crabs. The study aims to present data obtained using a monitoring system design at a mangrove crab hatchery in Brebes. The design of the monitoring system at the mangrove crab hatchery was successful in displaying environmental parameter data using Blynk software. Four parameters were monitored air humidity, air temperature, water temperature, and distance. Through descriptive statistical analysis of data from November, the air humidity was found to range from 65-98%, air temperature from 24-31°C, water temperature from 27-34°C, and the distance between the sensor and the sea surface from 17-69 cm. Based on this data, the water quality at the mangrove crab hatchery in Brebes is deemed suitable for the habitat and cultivation of mangrove crabs.
Keyword: blynk, hatchery, kepiting bakau, Suhu, sistem monitoring

Judul: Performance of Soft Shell Crab Production and Cultivation Business in Apartment Systems with Different Seed Sources
Abstrak: Pengembangan budidaya kepiting bakau di kawasan perkotaan (urban aquaculture) menggunakan sistem apartemen dengan resirkulasi air masih membutuhkan benih dari hasil tangkapan alam. Benih dari lokasi penangkapan yang berbeda akan mempengaruhi kelangsungan hidup, pertumbuhan, dan produktivitas kepiting bakau dalam sistem akuakultur, terkait dengan kondisi habitat asal kepiting, cara penangkapan, penanganan dan transportasi hasil tangkapan. Kepiting bakau berukuran 50-120 g sebanyak 90 ekor didatangkan dari Bekasi, Tangerang, dan Subang. Kepiting bakau ditangkap di tambak tradisional dan hutan mangrove menggunakan bubu dan pancingan, lalu ditampung selama 2- 3 jam pada drum plastik, karung, dan boks stirofoam, kemudian diangkut secara kering menggunakan keranjang berukuran 48 × 35,5 × 16,5 cm, selanjutnya diaklimatisasi dengan metode pencipratan dan perendaman. Kepiting bakau kemudian dipelihara dalam sistem apartemen selama 30 hari, dan diberi makan ikan rucah selar kuning sebanyak 2-5 g/ekor secara at satiation satu kali dalam sehari pada pukul 17.00 WIB. Hasil penelitian menunjukkan sumber benih dari Kabupaten Bekasi, Tangerang, Subang tidak berpengaruh terhadap kinerja produksi kepiting soka, yaitu kelangsungan hidup 73,33±5,77%, 70,00±10,00%, dan 50,00±10,00% dengan produksi kepiting soka antara 6,67-33,33%. Hasil penjualan kepiting belum mencapai titik impas, kecuali pada kepiting yang berasal dari Tangerang., Development of mangrove crab cultivation in urban areas (urban aquaculture) using an apartment system with water recirculation still requires seeds from natural catch. Seeds from different fishing locations will influence the survival, growth and productivity of mud crabs in the aquaculture system, related to the conditions of the crab's native habitat, methods of catching, handling and transporting the catch. The 90 mangrove crabs measuring 50-120 g were imported from Bekasi, Tangerang and Subang. Mangrove crabs are caught in traditional ponds and mangrove forests using traps and fishing rods, then stored for 2-3 hours in plastic drums, sacks and styrofoam boxes, then transported dry using baskets measuring 48 × 35.5 × 16.5 cm, then acclimatized by splashing and immersion methods. Mangrove crabs are then kept in an apartment system for 30 days, and fed 2-5 g of yellow trevally trash fish/head at satiation once a day at 17.00 WIB. The results of the research showed that seed sources from Bekasi, Tangerang, Subang Regencies had no effect on the production performance of soft shell crabs, namely survival of 73.33 ± 5.77%, 70.00 ± 10.00%, and 50.00 ± 10.00% with soft shell crab production between 6.67-33.33%. The sales of crabs have not yet reached the break-even point, except for crabs originating from Tangerang.
Keyword: crab catching, molting, survival

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
Keyword: