Judul: Drought Analysis Using the PDSI Index in the Southeast Asia Region (Case study: Indochina Peninsula, Malay Peninsula, and  Sumatera Island).
Abstrak: Kekeringan dapat memiliki dampak yang cukup besar di berbagai wilayah termasuk di kawasan Asia Tenggara. Palmer drought Severity Index (PDSI) merupakan salah satu indeks kekeringan yang menggunakan konsep neraca air, dengan data masukan berupa presipitasi dan evapotranspirasi, untuk mendapatkan hasil luaran berupa nilai tingkat keparahan. Penelitian ini bertujuan untuk mengetahui, menganalisis, serta membandingkan sebaran tingkat keparahan kekeringan berdasarkan indeks PDSI pada beberapa wilayah Asia Tenggara, yakni Semenanjung Indocina, Semenanjung Malaya, dan Pulau Sumatera. Hasil distribusi nilai PDSI di Semenanjung Indocina, Malaya, dan Sumatera menunjukan pola spasial dan temporal yang tidak selalu mengikuti pola curah hujan bulanan. Fenomena yang mempengaruhi anomali curah hujan seperti El-Nino dan Indian Ocean Dipole (IOD) juga dapat meningkatkan distribusi dan nilai PDSI di seluruh wilayah kajian. Wilayah Indocina menunjukkan kondisi kekeringan dengan tingkat keparahan tinggi yang lebih sering terjadi dibandingkan dengan Semenanjung Malaya dan Pulau Sumatera. Wilayah Malaya dan Sumatera menunjukkan pola temporal yang serupa dengan nilai tingkat keparahan kekeringan yang cenderung sedang, akan tetapi dapat meningkat secara drastis di saat tertentu. Tren peningkatan signifikan nilai PDSI sebagian besar hanya terjadi di wilayah Indocina bagian tengah atas (Myanmar), sedangkan penurunan signifikan terjadi di bagian selatan Indocina (Kamboja, Vietnam)., Drought can have significant impacts in various regions, including Southeast Asian areas. Palmer Drought Severity Index (PDSI) is one of the drought indices that utilizes the concept of water balance, with precipitation and evapotranspiration as input data, to determine severity levels. This study aims to understand, analyze, and compare the distribution of drought severity levels based on the PDSI index in several Southeast Asian regions, namely Indochina Peninsula, Malaya Peninsula, and Sumatra Island. Distribution of PDSI values across the study areas reveals spatial and temporal patterns that do not always follow monthly rainfall patterns. Phenomena influencing rainfall anomalies such as El-Nino and IOD can also enhance the distribution and PDSI values throughout the study areas. Indochina region shows drought conditions with high severity levels that occur more frequently compared to the Malay Peninsula and Sumatra. Malay Peninsula and Sumatra exhibit similar temporal patterns with moderately severe drought severity levels, but they can increase dramatically at certain times. Significant increasing trends in PDSI values mainly occur in the upper central Indochina region (Myanmar), while significant decreases occur in the lower parts of Indochina (Cambodia, Vietnam).
Keyword: indeks palmer, kekeringan meteorologi, kekeringan regional, tren

Judul: Pemetaan Indeks Kekeringan dan Pola Tanam Menggunakan Metode Palmer (Studi Kasus: Jawa Barat)
Abstrak: Drought is closely related to rainfall decrease could affect the decline in rice production in one of rice production centers: West Java. This research aims to determine the drought level, drought index distribution map, and cropping pattern in West Java. Monthly rainfall, monthly average temperature, soil type, and land use data is processed by Palmer method. The highest value index is 22 and the lowest is -34. Area with the highest drought level is Northern area of West Java, while the central and southern part of West Java area tends to be wet. Peak of the drought occurs in August and September. On the strong El Nino years, the rainfall value becomes lower followed by drought index value. In the non-irrigated land, cropping patterns that can be applied is paddy-paddy-crop with the beginning of the season in November, while for the irrigated land rice can be planted up to three times a year. In the non-irrigated land at the north area that tends to be dryer, cropping patterns that can be applied is paddy-crop-crop with the beginning of planting season in December, if conditions are adequate irrigation of rice can be planted two or three times a year.
Keyword: Bogor Agricultural University (IPB), El Nino, Palmer index, drought, cropping pattern.

Judul: Grup dan Homomorfisma Grup pada Rubik Revenge
Abstrak: Rubik cube is a kind of puzzle game. A player must arrange rubik sides, which have been disordered, back to the position where every side has the same colour. This paper does not focus on the settlement solution, but instead on proving the existence of a group homomorphism between rubik movement group and S96 symmetric permutation group in rubik revenge. Firstly, it has been proved that rubik movement set is a group. Then, it also has been proved that the M set, which contains numeric labels of 1 until 96 in cubinos sides, is S96 symmetric permutation group.
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