Judul: Physicochemical Characteristics, Microbiology and  Market Test of Strawberry Rosela Yogurt Smoothies on Teenagers and Adults in  Bogor
Abstrak: Yogurt smoothies rosela stroberi merupakan yogurt yang telah mengalami perlakuan pengurangan kadar air dan penambahan ekstrak bunga rosela serta selai stroberi. Sebelum dipasarkan, produk ini perlu diuji keamanan serta peluang pasarnya. Penelitian ini bertujuan menganalisis karakteristik fisikokimia, mikrobiologi dan uji pasar yogurt smoothies rosela stroberi pada usia remaja dan dewasa di Bogor. Karakteristik fisikokimia yang diuji meliputi pH, aktivitas air (aw), viskositas dan total asam tertitrasi. Parameter mikrobiologi yang diuji adalah total bakteri asam laktat dan cemaran Salmonella sp . Parameter uji pasar yang diuji meliputi analisis persepsi dan preferensi konsumen serta korelasinya terhadap pola konsumsi yogurt. Uji pasar yang dilakukan menggunakan 100 orang responden yang terdiri dari 50 orang siswa SMAN 1 Bogor dan 50 orang Mahasiswa IPB University. Hasil penelitian menunjukkan karakteristik fisik (pH, aktivitas air, viskositasdan total asam laktat) telah memenuhi persyaratan SNI mutu yogurt. Karakteristik kima atau kandungan nutrisi serta karakteristik mikrobiologi yogurt smoothies telah memenuhi persyaratan mutu standar yogurt berdasarkan SNI. Hasil penelitian menunjukkan responden memiliki persepsi yang baik serta preferensi suka terhadap atribut yogurt smoothies. Preferensi konsumen mengenai warna kemasan, bahan kemasan, bentuk kemasan, keterangan dalam kemasan, rasa yogurt serta tekstur yogurt memiliki korelasi yang positif dengan rentang harga yogurt yang dibeli, frekuensi konsumsidan volume konsumsi yogurt., Strawberry Rosela Yogurt Smoothie is yogurt that has been processed by reducing the water content and adding rosela flower extract and strawberry jam. Before being marketed, these products need to be tested for safety and market opportunities. This study aims to analyze the physicochemical characteristics, microbiology and market tests of strawberry rosela yogurt smoothies in adolescents and adults in Bogor. The physicochemical characteristics tested included pH, water activity (aw), viscosity and total titrated acid. The microbiological parameters tested were total lactic acid bacteria and Salmonella sp. The market test parameters tested include analysis of consumer perceptions and preferences and their correlation with yogurt consumption patterns. The market test was carried out using 100 respondents consisting of 50 students from SMAN 1 Bogor and 50 students from IPB University. The results showed that the physical properties (pH, water activity, viscosity, and total lactic acid) fulfilled the SNI yogurt quality requirements. The chemical properties or nutritional content and microbiological properties of yogurt smoothies have met the requirements for yogurt quality standards based on SNI. The results showed that respondents had good perceptions and preferences on the attributes of smoothies yogurt. Consumer preferences regarding packaging color, packaging material, packaging shape, packaging description, yogurt taste and yogurt texture are positively correlated with the price range of yogurt purchased, frequency of consumption, and volume of yogurt consumption.
Keyword: karakteristik fisikokimia, karakteristik mikrobiologi, persepsi konsumen, preferensi konsumen

Judul: Physicochemical and Organoleptic Characteristic of Rosella Strawberry Yogurt Smoothies with Different Storage Time Length
Abstrak: Peningkatan permintaan pangan fungsional seperti yogurt mengalami peningkatan. Nilai tambah dan keunikan citarasa stirred yogurt dapat dilakukan dengan cara diversifikasi produk, salah satunya smoothies. Kualitas smoothies dapat ditingkatkan dengan melakukan penambahan bahan alami, seperti bunga rosella, stroberi, dan probiotik Lactobacillus plantarum IIA-1A5. Penelitian ini bertujuan mempelajari pengaruh lama waktu penyimpanan (0, 7, dan 14 hari) terhadap karakteristik fisikokimia dan organoleptik smoothies yogurt dengan penambahan selai rosella stroberi sebesar 15%. Karakteristik fisikokimia yang akan dianalisis meliputi pH, aw, viskositas, kadar protein, dan kadar lemak. Atribut uji organoleptik yang digunakan terdiri atas aroma, rasa, warna, dan tekstur. Data yang terkumpul dianalisis menggunakan ANOVA dengan tiga kali pengulangan. Hasil penelitian menunjukkan bahwa penyimpanan smoothies berpengaruh nyata (P<0,05) terhadap nilai pH dan viskositas, tetapi tidak berpengaruh nyata (P>0,05) terhadap aktivitas air. Hasil uji organoleptik tidak berpengaruh nyata (P>0,05) terhadap semua atribut penilaian. Berdasarkan hasil penelitian, smoothies yogurt memiliki karakteristik yang stabil selama penyimpanan., Demand for functional foods such as yogurt has increased. The added value and unique flavor of stirred yogurt can be done by diversifying the product, one of them is smoothies. The quality of smoothies can be improved by adding natural ingredients, such as rosella flowers, strawberries, and probiotic Lactobacillus plantarum IIA-1A5. This research aims to study the effect of storage time (0, 7, and 14 days) on the physicochemical and organoleptic characteristics of yogurt smoothies with the addition of 15% rosella strawberry jam. Physicochemical characteristics to be analyzed include pH, aw, viscosity, protein content, and fat content. The attributes of organoleptic tests used consist of aroma, taste, color, and texture. The collected data were analyzed using ANOVA with three repetitions. The results showed that the storage of smoothies had a significant effect (P<0,05) on pH and viscosity values, but no significant effect (P>0,05) on water activity. Organoleptic test results had no significant effect (P>0,05) on all assessment attributes. Yogurt smoothies have stable characteristics during storage time.
Keyword: characteristic, rosella, smoothies, strawberry, time length

Judul: The Construction of Greedy SVP LLL Algorithm
Abstrak: A lattice is a set of all integer linear combination of a set of linearly independent vectors in ℝ𝑛���. The independent vectors are called bases of lattice. Any lattice can be generated from many bases, and these bases have the same cardinality. In the lattice, the most fundamental and renowned problem is the Shortest Vector Problem (SVP). SVP is a tracking problem of the shortest nonzero vector in a lattice with equivalent bases. In two dimensions, SVP problem has resolved exactly by Gauss’ algorithm. When the lattice dimension is higher than two, A.K. Lenstra, H.W. Lenstra and L. Lovasz gave a LLL algorithm to compute approximation of nonzero shortest vector in the lattice. Reduced bases solution obtained from LLL algorithm still be an approximation and has polynomial running time of arbitrary dimension which large enough. In 1994, Schnoor and Euchner modified this LLL algorithm as a new variant which later was named deep insertion LLL algorithm. This algorithm is a modified version of the LLL algorithm to the terms of the exchange step to improve the accuracy of output of LLL reduced bases and applying it to the subset sum problem. The purpose of this research are: (1) Reconstruct the LLL algorithm and deep insertion LLL algorithm using a geometric approach. (2) Construct a greedy SVP LLL algorithm. (3) Implement the three algorithms in a symbolic programming language, and evaluate them experimentally. A bases ℬ=[𝐛���1,𝐛���2,…,𝐛���𝑛���] in ℝ𝑚��� is called reduced LLL with parameter 𝛿��� if satisfies: (a) |𝜇���𝑗���𝑖���|≤12, for every integer 𝑖���,𝑗��� with 1≤𝑖���<𝑗���<𝑛���. (b)𝛿���‖𝜋���𝑗���(𝐛���𝑗���)‖2≤‖𝜋���𝑗���(𝐛���𝑗���+1)‖2, for 𝑗���=1,2,…,𝑛���−1,where 𝛿��� is a reduced parameter of real numbers with 14<𝛿���<1. The first requirement is the reduced basis 𝛿��� must “nearly orthogonal” and in its computation case, this requirement can be reached out by using the Gram-Schmidt’s orthogonalization. While the second requirement is called exchange step, or used to called as Lovasz condition. By using both of these requirements, then they establish the LLL algorithm. Then, Schnoor and Euchner modify the LLL algorithm based on the requirements of the exchange step called the deep insertion LLL algorithm, where the exchange step is based on the comparison of the projected vector in orthogonal complement [𝐛���1,𝐛���2,…,𝐛���𝑘���−1]⊥ after j-th reduction. To construct greedy SVP LLL algorithm, the requirements of the exchange step is based on purely by comparing norm of lattice 𝐛���𝑗��� with norm lattice 𝐛���𝑖��� for 𝑖���=1,2,3…,𝑗���−1. The process of insertion reduced vector after the exchange step also has done greedily. Then, we calculate the number of arithmetic operation in greedy SVP LLL algorithm for further analysis. The result of our exprimentation for three algorithms on the certain matrix size shows that the running time of the three algorithms increases propotional to the size of the matrix. The result also shows that by using 𝛿���=34 for the LLL algorithm and the deep insertion LLL algorithm, and the greedy SVP LLL algorithm which is a new variant made by using no parameter of 𝛿���, outperform of the other of two previous algorithm in terms of speed with the same output.
Keyword: LLL algorithm, LLL deep insertion algorithm, greedy SVP LLL algorithm