Judul: Pengaruh Psychological Factors, Financial  Literacy, dan Paylater Misuse terhadap Compulsive Buying
Abstrak: Peningkatan tren belanja online melalui e-commerce di masa pandemi Covid-19 turut didukung dengan perkembangan metode pembayaran digital, salah satunya paylater. Paylater memungkinkan konsumen untuk membeli barang sekarang dan membayarnya kemudian dengan cicilan setiap bulan. Pertumbuhan paylater di Indonesia dapat mendorong perkembangan ekonomi digital dan selaras dengan tujuan pembangunan berkelanjutan (Sustainable Development Goals/SDGs). Namun, apabila tidak dikendalikan, penggunaan paylater justru berisiko memicu perilaku compulsive buying dan meningkatkan jumlah hutang yang dimiliki konsumen. Penelitian ini bertujuan untuk menganalisis karakteristik pengguna paylater di Jabodetabek, menganalisis pengaruh psychological factors dan financial literacy terhadap paylater misuse, dan menganalisis pengaruhnya terhadap compulsive buying. Penelitian ini menggunakan sampel sebanyak 275 responden pengguna paylater di Jabodetabek. Sampel penelitian ditentukan menggunakan metode non-probability sampling jenis convenience sampling dan quota sampling. Selanjutnya, hasil penelitian dianalisis menggunakan analisis deskriptif dan Structural Equation Modeling-Partial Least Squares (SEM-PLS). Hasil penelitian ini menunjukkan bahwa psychological factors, financial literacy, dan paylater misuse memiliki pengaruh yang positif dan signifikan terhadap compulsive buying., The increasing trend of online shopping through e-commerce during the Covid-19 pandemic is also supported by the development of digital payment method, one of which is paylater. Paylater allows consumers to buy now and pay later in monthly installments. Paylater growth in Indonesia can encourage the development of the digital economy and is in line with sustainable development goals (SDGs). However, if not controlled, the use of paylaters actually risks triggering compulsive buying behavior and increasing the amount of debt owned by consumers. This research aims to analyze the characteristics of paylater users in Jabodetabek, analyze the influence of psychological factors and financial literacy toward paylater misuse, and analyze its influence toward compulsive buying. The sample of this research was 275 respondents of paylater users in Jabodetabek. The research sample was determined using the non-probability sampling method, types convenience sampling and quota sampling. Furthermore, the research results were analyzed using descriptive analysis and Structural Equation Modeling-Partial Least Squares (SEM-PLS). The results of this research show that psychological factors, financial literacy, and paylater misuse have a positive and significant effect on compulsive buying.
Keyword: compulsive buying, paylater, SDGs, SEM-PLS

Judul: Analysis of the Effect of Utilitarian and  Hedonic Attributes on Impulse Buying with Cognitive and Affective Attitude
Abstrak: Pengguna internet di Indonesia tahun demi tahun mengalami peningkatan dari tahun ke tahun. Perkembangan tersebut membuat masyarakat menggunakan paylater menjadi salah satu jenis fintech technology yang sering digunakan oleh masyarakat. Saat konsumen berbelanja online, terdapat tiga jenis atribut, diantaranya, atribut utilitas, dan atribut hedonis. Atribut utilitas ini dapat memengaruhi perilaku konsumen yang merujuk pada cognitive attitude dan atribut hedonis ini berhubungan dengan persepsi konsumen mengenai utilitas dan fungsi dari sebuah objek yang merujuk pada sikap afektif. Cognitive dan affective attitude ini memiliki hubungan timbal balik yang dapat memungkinkan perilaku pembelian impulsif. Oleh karena itu, peneliti ingin menganalisis pengaruh utilitarian dan hedonic attributes terhadap perilaku impulse buying pada pengguna paylater di jabodetabek dengan pendekatan cognitive dan affective attitude. Penelitian ini menggunakan sampel sebanyak 235 responden pengguna paylater di Jabodetabek. Sampel penelitian ditentukan menggunakan metode non-probability sampling. Selanjutnya, hasil penelitian dianalisis menggunakan analisis deskriptif dan Structural Equation Modeling-Partial Least Squares (SEM-PLS)., Internet users in Indonesia are increasing year by year. This development makes people use paylater as one type of fintech technology that is often used by the public. When consumers shop online, there are three types of attributes, including utility attributes and hedonic attributes. These utility attributes can influence consumer behaviour which refers to cognitive attitude and these hedonic attributes relate to consumer perceptions of the utility and function of an object which refers to affective attitude. This cognitive and affective attitude has a reciprocal relationship that can enable impulsive buying behaviour. Therefore, researchers want to analyse the effect of utilitarian and hedonic attributes on impulse buying behaviour in paylater users in Jabodetabek with a cognitive and affective attitude approach. This study used a sample of 235 paylater user respondents in Jabodetabek. The research sample was determined using non probability sampling method. Furthermore, the research results were analysed using descriptive analysis and Structural Equation Modeling-Partial Least Squares (SEM-PLS).
Keyword: affective attitude, cognitive attitude, hedonic attributes, impulsive  buying, utilitarian attributes

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.
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