Judul: Hedonic Price Index for Mobile Phone Based on E-Commerce Data
Abstrak: Big data provides an opportunity to build datasets that fit specific requirements for research. One of the global concerns about big data is how to utilize it for measuring price index. Due to the proliferation of e-commerce sites, a vast amount of prices information followed by the product specifications are available on the internet. This information would allow researchers to calculate hedonic indices for the products undergo rapid quality change like a mobile phone. A method to gather big data is by implementing a large-scale data collection on the web with an automated scraping process. In this study, a web scraper was built using python language to extract information about product, price and characteristics from various e-commerce displayed on the IPrice.co.id website. The data extraction was conducted weekly from January to June 2020 and gathered more than 34,000 records in total. A database containing comprehensive specifications of 458 types of mobile phones was developed based on information from gsmarena.com to validate the scraped data. The method used for calculating the hedonic price index is the double imputation method. One of the steps in this method is to construct a hedonic regression model for datasets consists of two consecutive periods. Due to the presence of outliers and leverage points, robust regression with MM (Multi-Stage Method) estimation was used to get a reliable and efficient estimate of the parameters. Due to the lack of information on the product quantity for weighting, several alternative weighting scenarios were taken. The first is weighting based on the release year mobile phone, the second is by using market share as a proxy for weighting, and the third is the combination of both. The result shows that price movement based on online transactions captured in this study do not reflects the one from offline transactions captured in the Consumer Price Index (CPI) produced by Badan Pusat Statistik (BPS). The weekly indices have a wider fluctuation than the CPI. Weighting based on both release year of mobile phone and market share produces the most stabilized index.
Keyword: Hedonic Regression, Online Price Index, Web Harvesting

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: Closed Knight’s Tour pada Papan Catur Berbentuk Persegi Panjang dengan Ukuran Maksimal 8 × 8
Abstrak: Closed Knight’s Tour merupakan langkah kuda yang mengunjungi setiap kotak pada papan catur tepat satu kali dengan langkah kuda berawal dan berakhir pada kotak yang sama. Graf yang terbentuk dari closed knight’s tour dinotasikan sebagai graf G(m,n), dengan m adalah banyaknya baris dan n adalah banyaknya kolom. Graf tersebut memuat Hamiltonian cycle. Sebuah graf terhubung G adalah graf bipartite jika dan hanya jika graf tersebut tidak memiliki cycle dengan panjang ganjil. Papan catur yang memenuhi syarat cukup untuk memiliki closed knight’s tour adalah papan catur berukuran 5 × 6, 5 × 8, 6 × 6, 6 × 7, 6 × 8, 7 × 8, dan 8 × 8.
Keyword: bipartite, closed knight’s tour, hamiltonian cycle, knight’s tour, teori graf