Judul: The Influence of Chief’s Leadership Style on the Efectivity of Farmer Group in Pangkal Jaya Village, Nanggung Sub-distrcit, Bogor Disctrit
Abstrak: Dalam mengelola sebuah kelompok, diperlukan seorang ketua untuk mengajak anggota mencapai tujuan bersama. Gaya kepemimpinan ketua menjadi faktor yang mempengaruhi efektivitas kelompok tani. Tujuan penelitian ini adalah menganalisis pengaruh karakteristik individu petani dan kepemimpinan ketua terhadap efektivitas kelompok tani. Penelitian ini dilaksanakan di Desa Pangkal Jaya, Kecamatan Nanggung, Kabupaten Bogor. Jumlah responden dalam penelitian ini yaitu 70 responden yang ditentukan dengan proportional random sampling. Data yang diperoleh kemudian diolah dan dianalisis menggunakan metode SEM-PLS. Hasil penelitian menunjukkan bahwa kelompok tani di Desa Pangkal Jaya memiliki tingkat efektivitas yang tinggi. Karakteristik individu secara keseluruhan memiliki pengaruh yang tidak signifikan terhadap efektivitas kelompok tani. Kepemimpinan partisipatif memiliki pengaruh yang signifikan hanya terhadap kemampuan bekerja kelompok dan kepemimpinan orientasi prestasi memiliki pengaruh yang signifikan terhadap kepuasan anggota, kemampuan bekerja kelompok, dan produktivitas kelompok., In managing a group, a leader is needed to influence members to achieve common goals. The chairman’s leadership style is a factor that influences the effectiveness of farmer groups. The aim of this research is to analyze the influence of individual farmer characteristics and the leader's leadership on the effectiveness of farmer groups. This research was conducted at Pangkal Jaya Village, Nanggung District, Bogor Regency. The number of respondents in this research is 70 respondents who were determined by proportional random sampling. The data obtained was then processed and analyzed using the SEM-PLS method. The research results show that farmer groups in Pangkal Jaya have a high level of effectiveness. Individual characteristics have an insignificant influence on the effectiveness of farmer groups.Participative leadership has a significant influence only on group work ability and achievement-oriented leadership has a significant influence on member satisfaction, group work ability and group productivity.
Keyword: farmer group, group effectiveness, leadership style

Judul: Persepsi Anggota Kelompok Tani Padi terhadap Kepemimpinan Ketua Kelompok Tani di Kabupaten Kebumen, Jawa Tengah
Abstrak: In general, the behaviour of farmer group leaders strongly influences the changes in his group behaviour. If the leader is effectively influencing his members, they will behave as desired. Therefore, the leadership of farmer groups becomes a strategic issue on agricultural extension methodology through group approach. The farmer group leader could act for some leadership functions and figures to motivate and mobilize members to perform various activities to achieve the group goals. Perceptions related to the individual's opinions and judgments of a stimulus that will lead to motivation, willingness and feelings toward the stimulus. The correct perception of an object is necessary, because the perception is the basis of the formation of attitudes and behaviour. Thus, a good perception of the group members on the leadership of their group leaders is one of the main indicators of the success of a leader in bringing about the success of his farmer groups. This research aims to: (1) analyse the perception of group members on the leadership of farmer group leaders, (2) analyse the correlation between internal factors in the group members and their perceptions on the leadership of their group leader, (3) analyse the correlation between external factors in the group members and their perceptions on the leadership of their group leader, (4) analyse the success of farmer groups, and (5) analyse the correlation between perceptions of group members on the leadership of their group leader and the success of farmer groups. The design of this research is using methodology of survey to explain the correlation among the variables of this research. The population in this research are all farmers who are members of paddy farmer groups in Kebumen, Central Java Province. The respondent recruited by using stratified random sampling method based on class (typology) of abilities of farmer groups set by the Ministry of Agriculture, namely: Beginners, Intermediates 1, Intermediate 2, and Advanced (Pemula, Lanjut, Madya and Utama). The number of farmer groups (respondents) observed were 12 groups with details of three farmer groups in each typology of farmer groups, then 10 members from each group selected, so the total number of respondents was 120 farmers. The research was conducted from August to November 2012. The data analysis includes: (1) descriptive analysis: the frequency distribution and different test of non-parametric Kruskal-Wallis, and (2) inferential analysis: Rank Spearman correlation. Analysis helped by SPSS software version 20.0. The result of this research shows that the perception of members on the leadership of the farmer groups’ leader is high; the group leader has performed his function as a group leader well. The higher the grade of ability of the farmer groups, the perception of members on the leadership of their group leaders tends to become better. Internal factors of the group members that consist of age, formal education, land owned, motivation, and a cosmopolitan issue of the area have real positive correlation to the perception of members on the leadership of the farmer groups’ leaders. The external factors of the group members that consist of the availability of information, the role of agriculture extension worker,
Keyword: 

Judul: Hamiltonian formulation for linear waves motion in two layers fluid
Abstrak: The surface wave could be considered as a wave that separates two fluids, namely water and air. Based on this assumption, it is introduced the interfacial wave, a wave between two layers of fluid with different density. The formulation of interfacial waves motion begins with deriving the base equation of irrotational ideal fluid. Furthermore, according to irrotational fluid assumption, the base equation can be stated in velocity potential. In this derivation, the fluids domain is assumed to be restricted by rigid lid boundary conditions, both at the upper and lower limit. Therefore, the interfacial waves motion can be explained in a hamiltonian formulation. In the hamiltonian formulation, total energy is defined as the sum of kinetic and potential energy. The hamiltonian system is obtained from reduction of kinetic energy by using the Dirichlet Neumann Operator. The resulted kinetic energy equation is nonlinear. Therefore, this form is linearized by first part of the Taylor expansion. This linearization gives a dispersion relation of linear wave. Based on this dispersion relation, the phase speed of the linear wave depends on the density ratio of the two layers fluid.
Keyword: