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All Journal CAUCHY: Jurnal Matematika Murni dan Aplikasi Jurnal Ilmiah Matematika Operations Research: International Conference Series International Journal of Quantitative Research and Modeling International Journal of Humanities, Law, and Politics International Journal of Health, Medicine, and Sports International Journal of Linguistics, Communication, and Broadcasting
Vimelia, Willen
Unknown Affiliation
Humanities Computer Science & IT Decision Sciences, Operations Research & Management Dentistry Economics, Econometrics & Finance Engineering Environmental Science Health Professions Languange, Linguistic, Communication & Media Law, Crime, Criminology & Criminal Justice Mathematics Medicine & Pharmacology Nursing Physics Public Health Social Sciences

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Optimal Portfolio Risk Analysis Using the Monte Carlo Method Kahar, Ramadhina Hardiva; Kaerudin, Nandira Putri; Vimelia, Willen
Operations Research: International Conference Series Vol. 4 No. 4 (2023): Operations Research International Conference Series (ORICS), December 2023
Publisher : Indonesian Operations Research Association (IORA)

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.47194/orics.v4i4.276

Abstract

Investment is an activity carried out with the expectation of gaining profits in the future through the management of investment assets. Investment assets can include buildings, gold, and stocks. Investment activities are inseparable from the concepts of return and risk. The relationship between the expected rate of return and the level of risk is linear. However, risk can be avoided or reduced through portfolio diversification. Evaluating investment risk is crucial for investors to determine which risky assets to choose. One popular method for assessing the risk of a portfolio is using Value at Risk (VaR). In VaR calculations, Monte Carlo is considered the most effective method. In this paper, a risk analysis of the optimal portfolio is conducted using the Monte Carlo method. The analyzed optimal portfolio consists of shares in BBCA, TLKM, BBRI, BBNI, BMRI, ADRO, GGRM, and UNTR. The results indicate that the potential loss for the investor is no more than IDR 705.634,- with an initial fund of 1 billion. 
Reactualizing Indonesia's Legal System: A Comprehensive Critique and Proposals for Reform Vimelia, Willen; Aglia, Arla; Prabowo, Agung
International Journal of Humanities, Law, and Politics Vol. 2 No. 2 (2024): International Journal of Humanities, Law, and Politics
Publisher : Communication in Research and Publications (CRP)

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.46336/ijhlp.v2i2.85

Abstract

This text provides a comprehensive critique of the legal system and law enforcement in Indonesia, addressing challenges and proposing solutions. It discusses issues such as formalism, case backlog, and the need for innovation in judicial decision-making. The analysis emphasizes the importance of reactualizing the legal system, integrating local laws into the national framework, and implementing institutional reforms for law enforcement agencies. Additionally, the text advocates for empowering society through increased access to government functioning and legal awareness. The role of bureaucracy in development and challenges posed by political and constitutional phenomena are explored. The article outlines four key problems requiring attention: legal system reactualization, institutional restructuring, community empowerment, and bureaucratic empowerment. Ultimately, the analysis calls for a paradigm shift in legal philosophy and proposes improvements across various facets of Indonesia's legal system and law enforcement.
Analysis of Public Policy and Criminal Law in The Perspective of Consumer Protection for Online Loan Users in Indonesia Kalfin; Vimelia, Willen; Haq, Fadiah Hasna Nadiatul
International Journal of Humanities, Law, and Politics Vol. 2 No. 2 (2024): International Journal of Humanities, Law, and Politics
Publisher : Communication in Research and Publications (CRP)

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.46336/ijhlp.v2i2.86

Abstract

The development of online loan services or pinjol in Indonesia raises new problems in consumer protection. Many cases of fraud and misuse of customer personal data are very concerning. The government has not had specific regulations regarding online loans. The existing regulations are merely appeals and suggestions for fintech pinjol to conduct business responsibly. In fact, stricter regulatory and enforcement steps are needed to address the increasing violations that harm consumers. This study aims to analyze public policies and criminal law in the perspective of protecting pinjol consumers in Indonesia. This research uses a normative legal approach with statute and conceptual approaches. The results are expected to provide recommendations for more effective legal protection for online lending consumers in Indonesia, as well as enriching academic literature on fintech and digital consumer protection. The conclusion is that firmer public policy and criminal law provisions are needed to protect consumer rights in using online loan services which currently have weak legal protection.
Stability, Characterization, and Antibacterial Activity of Cinnamon (Cinnamomum burmanii) Extract Mask Preparations as Potential Skin Care Products Lianingsih, Nestia; Yuningsih, Siti Hadiaty; Vimelia, Willen
International Journal of Health, Medicine, and Sports Vol. 2 No. 2 (2024): International Journal of Health, Medicine, and Sports
Publisher : Corespub

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.46336/ijhms.v2i2.104

Abstract

This study aims to evaluate the stability, physical-chemical characteristics and antibacterial activity of a cinnamon extract (Cinnamomum burmanii) mask preparation. Cinnamon extract is obtained through the maceration method using 96% ethanol. The physical-chemical characteristics of the preparations were evaluated including water content, ash content, as well as phytochemical tests to identify active compounds such as alkaloids, flavonoids, tannins and saponins. Stability tests were carried out for 8 weeks at room temperature (25°C-30°C) and accelerated temperature (40°C), with pH and organoleptic testing parameters. Apart from that, a preference test for aroma, texture and color is also carried out using a specified rating scale. The antibacterial activity of the preparation was evaluated using the disc diffusion method against Staphylococcus aureus. The research results showed that the cinnamon extract mask preparation had good stability, physical-chemical characteristics according to standards, and promising antibacterial activity, especially at an extract concentration of 12%.
Strategies for Anticipating Speech Production Errors in the Public Speaking Context: Psycholinguistic Analysis and Improving Public Speaking Ability Cahyandari, Rini; vimelia, willen; salih, yasir
International Journal of Linguistics, Communication, and Broadcasting Vol. 2 No. 1 (2024): International Journal of Linguistics, Communication, and Broadcasting
Publisher : Communication In Research And Publications

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.46336/ijlcb.v2i1.92

Abstract

This research explores and analyzes various aspects related to public speaking and speech production errors in real life contexts. Through a literature review, this research explains the types of speech production errors, their causes, and strategies to anticipate these errors. This research also links speech production errors with public speaking, highlighting the importance of psycholinguistic understanding in this regard. The research results show that anticipating speech production errors is the key to improving public speaking skills. Anticipation strategies include preparing the topic well, maintaining composure, focusing, and using familiar vocabulary. Speech production errors can disrupt the flow of a presentation, so a deep understanding of these aspects is very important in public speaking.
Investment Portfolio Optimization in Renewable Energy Stocks in Indonesia Using Mean-Variance Risk Aversion Model Vimelia, Willen; Riaman, Riaman; Sukono, Sukono
International Journal of Quantitative Research and Modeling Vol. 5 No. 1 (2024)
Publisher : Research Collaboration Community (RCC)

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.46336/ijqrm.v5i1.601

Abstract

Climate change is a phenomenon that has been occurring for quite some time. However, the increasingly felt impacts of climate change necessitate human action to mitigate these effects. One way to address this issue is by transitioning from conventional or non-renewable energy sources to renewable energy. This step undoubtedly has implications for various aspects, such as investments. Naturally, investors are beginning to turn their attention to the field of renewable energy as a new target. Investments are inherently associated with risks and returns One approach to maximizing returns is through portfolio optimization. One well-known method in portfolio optimization is the Mean-Variance method, also known as the Markowitz method, as it was first introduced by Harry Markowitz. In this research, an optimal portfolio is generated with weights of 0.1470 for ADRO; 0.1939 for MEDC; 0.2143 for ITMG and 0.4449 for RAJA. With this composition of optimal portfolio weights, the expected return is obtained at 0.002252, and the return variance is 0.000496.
Mean-Variance Portfolio Optimization with Lot Size Constraints in Energy Stocks: A Monte CarloApproach Vimelia, Willen; Riaman, Riaman; Sukono, Sukono
CAUCHY: Jurnal Matematika Murni dan Aplikasi Vol 10, No 1 (2025): CAUCHY: JURNAL MATEMATIKA MURNI DAN APLIKASI
Publisher : Mathematics Department, Universitas Islam Negeri Maulana Malik Ibrahim Malang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.18860/cauchy.v10i1.32159

Abstract

Stock investment requires portfolio optimization strategies that maximize returns and consider risks and practical constraints, such as target lot sizes. These constraints are crucial to ensuring the realistic implementation of portfolios in compliance with market regulations, particularly in Indonesia, where 1 lot equals 100 shares. However, existing research on the Mean-Variance model and Monte Carlo simulation has rarely incorporated target lot constraints, limiting the applicability of these models in real-world scenarios. To bridge this gap, this study conducts a systematic literature review (SLR) on portfolio optimization in Indonesia's energy sector stocks, focusing on the Mean-Variance model, risk aversion, Monte Carlo simulation, and target lot constraints. The PRISMA framework guides this SLR, with bibliometric analysis performed using RStudio. A rigorous selection process from Scopus and ScienceDirect databases yielded 13 relevant articles for in-depth analysis creates a more practical and effective approach to portfolio management. This advancement enables investors to achieve balanced portfolios that are both theoretically robust and feasible in practice. The study contributes significantly to optimizing investment strategies for Indonesia’s energy sector and opens avenues for further research into practical portfolio optimization methods.
Penerapan Sirkuit Hamilton Untuk Menentukan Rute Terpendek Perjalanan Mudik Kendaraan Roda Empat Putri, Estu; Razanah, Khalilah; Vimelia, Willen; Wijaya, Silvia; Hardiva, Ramadhina; Sylviani, Sisilia
Jurnal Ilmiah Matematika Vol. 12 No. 2 (2025)
Publisher : Universitas Ahmad Dahlan

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.26555/jim.v12i2.31058

Abstract

Penelitian ini bertujuan untuk menentukan rute terpendek dalam perjalanan mudik kendaraan roda empat dari Kota Jakarta menuju Kota Bandung. Latar belakang atau alasan dari dilakukannya penelitian ini yaitu karena ketika menjelang hari raya besar keagamaan, salah satunya Idul Fitri mayoritas masyarakat memilih untuk mudik menggunakan kendaraan jalur darat yang dimana merupakan salah satu transportasi terpadat setiap tahunnya. Maka dari itu, dicari rute mudik terpendek untuk menempuh perjalanan menuju ke kampung halaman. Rute terpendek yang dicari tidak hanya mempertimbangkan jarak saja, tetapi juga mempertimbangkan keamanan dan kenyamanan sehingga rute yang dihasilkan adalah rute yang paling optimum yang dapat dilewati dari kota asal ke kota tujuan. Metode yang digunakan dalam melakukan penelitian ini adalah Nearest Neighbor Method yaitu cara untuk melakukan pencarian sirkuit hamilton dengan rute terpendek. Pengumpulan data dilakukan dengan cara melihat jarak dari Kota Jakarta sampai dengan titik-titik drop-off di Kota Bandung. Hasil dari penelitian ini menunjukkan bahwa rute terpendek untuk perjalanan mudik menggunakan kendaraan roda empat dari Kota Jakarta menuju Kota Bandung dengan beberapa titik drop-off diawali dari Terminal Ledeng dilanjutkan ke Terminal Sadang Serang kemudian Terminal Tegalega lalu Terminal Leuwi Panjang selanjutnya Terminal Caringin diakhiri dengan Terminal Ciroyom dan kembali lagi ke Terminal Ledeng dengan jarak tempuh 30,2 km
Co-Authors Aglia, Arla Agung Prabowo Haq, Fadiah Hasna Nadiatul Hardiva, Ramadhina Kaerudin, Nandira Putri Kahar, Ramadhina Hardiva kalfin Kalfin Lianingsih, Nestia Putri, Estu Razanah, Khalilah Riaman Riaman, Riaman Rini Cahyandari Salih, Yasir Silvia Wijaya Sisilia Sylviani Sukono . Yuningsih, Siti Hadiaty