Judul: Serial Graph-Validation Queue (SG-VQ) Scheme in Client-Server System
Abstrak: Di era saat ini, real-time collaboration semakin berkembang dan memungkinkan pengguna untuk terhubung dari lokasi berbeda melalui aplikasi yang didukung arsitektur klien-server. Misalnya, fitur seperti desktop sharing untuk berbagi layar dan berbagi dokumen yang memungkinkan pengguna mengakses dokumen yang sama secara bersamaan. Namun, akses database secara simultan oleh klien dan modifikasi data dapat menyebabkan data tidak konsisten. Oleh karena itu, kontrol konkurensi sangat penting. Pemrosesan secara bersamaan dapat mempersulit proses penerapan dan menurunkan kinerja server. Object caching menyajikan alternatif untuk mengatur lalu lintas transaksi. Penelitian ini memodifikasi skema kontrol konkurensi optimis yang memanfaatkan object caching, yaitu skema Validation Queue (VQ) menjadi skema Serial Graph-Validation Queue (SG-VQ). Seperti skema VQ, SG-VQ menggunakan arsitektur klien-server dan object caching. Sebagai bagian dari algoritma validasi, sisi cache menerapkan algoritma validasi berbasis queue, sedangkan sisi server menggunakan algoritma validasi berbasis graph. Penelitian ini memvalidasi SG-VQ melalui transaksi hipotetik yang dibagi dalam tiga kasus dan menggambarkan pemanfaatan serial graph, kasus konflik, serta kasus pola siklik., In the current era, real-time collaboration is growing and enabling users to connect from different locations through applications supported by client-server architecture. For instance, features like desktop sharing for screen sharing and document sharing that allows users to simultaneously access the same document. However, simultaneous database access by clients and data modifications can lead to inconsistent data. Therefore, concurrency control is essential. Concurrent processing can complicate the commit process and degrade server performance. Object caching presents an alternative for managing transaction traffic. This study modifies an optimistic concurrency control scheme utilizing object caching, namely the Validation Queue (VQ) scheme, into the Serial Graph-Validation Queue (SG-VQ) scheme. Like the VQ scheme, the SG-VQ employs the client-server architecture and object caching. As part of the validation algorithm, the cache side adopts a queue-based validation algorithm, while the server side utilizes a graph-based validation algorithm. The research validates the SG-VQ with hypothetical transactions in three cases, illustrating the utilization of serial graphs, conflict case, and cyclic case.
Keyword: Klien-server, Kontrol konkurensi, Serial Graph

Judul: Mathematical Study for Proving Correctness of the  Serial Graph-Validation Queue (SG-VQ) Scheme
Abstrak: Selama beberapa tahun terakhir, terdapat peningkatan signifikan dalam kemampuan melakukan pekerjaan berbasis informasi dari jarak jauh. Peningkatan ini didukung oleh meluasnya penerapan aplikasi berbasis real-time collaboration. Aplikasi real-time collaboration memungkinkan banyak pengguna untuk bekerja secara bersamaan, bahkan ketika masing-masing berada terpisah secara geografis. Adapun aplikasi dengan fitur real-time collaboration biasanya mengadopsi arsitektur klien-server. Karena klien dapat mengakses server secara bersamaan, bahkan melakukan perubahan data, sistem klien-server memerlukan mekanisme kontrol konkurensi untuk menjaga konsistensi data. Sejumlah penelitian telah dilakukan untuk mengembangkan skema yang dapat diterapkan pada sistem klien-server, seperti skema Validation Queue (VQ) yang menggunakan cache objek di sisi klien. Skema ini kemudian dimodifikasi menjadi skema Serial Graph-Validation Queue (SG-VQ), yang menggunakan algoritma validasi berdasarkan queue di sisi klien dan graph di sisi server. Penelitian ini berfokus pada verifikasi kebenaran skema SG-VQ dengan menggunakan serializability sebagai indikator. Menerapkan grafik transaksi bebas siklus adalah syarat perlu dan syarat cukup untuk mencapai serializability. Untuk membuktikan Teorema, telah dirumuskan pernyataan matematika yang melibatkan sepuluh definisi, dua proposisi, dan tiga lemma. Pembuktian diawali dengan Lemma 1 yang menjamin bahwa urutan eksekusi secara global akan direfleksikan secara konsisten pada setiap klien k yang memunculkan transaksi terkait. Selanjutnya, Lemma 2 dan Lemma 3 menunjukkan bahwa transaksi konkuren pada skema SG-VQ dapat diserialkan. Hasil penelitian ini menunjukkan bahwa skema SG-VQ dapat menjalankan operasinya dengan benar, sesuai dengan Teorema Serializability Skema SG-VQ yang menyatakan bahwa setiap history (H) dari SG-VQ bersifat serializable., Over the past few years, there has been a significant increase in the ability to perform information-based work remotely. The widespread adoption of real-time collaboration applications has supported this increase. These applications enable many users to work simultaneously, even when geographically separated. Applications with real-time collaboration features typically adopt a client-server architecture. Since clients can access the server simultaneously and change data, the client-server system requires a concurrency control mechanism to maintain data consistency. Several studies have been conducted to develop schemes that can be applied to client-server systems, such as the Validation Queue (VQ) scheme, which uses object caching on the client side. This scheme was later modified into the Serial Graph-Validation Queue (SG-VQ) scheme, which uses a validation algorithm based on a queue on the client side and a graph on the server side. This research focuses on verifying the correctness of the SG-VQ scheme using serializability as an indicator. Applying a cycle-free transaction graph is a necessary and sufficient condition for achieving serializability. A mathematical statement has been formulated to prove the theorem involving ten definitions, two propositions, and three lemmas. The proof begins with Lemma 1, which ensures that the execution order is globally reflected consistently on each client k that issues the related transactions. Subsequently, Lemma 2 and Lemma 3 demonstrate that concurrent transactions in the SG-VQ scheme can be serialized. The results of this study indicate that the SG-VQ scheme can operate correctly, following the SG-VQ Scheme Serializability Theorem, which states that every history (H) of SG-VQ is serializable.
Keyword: Correctness, Klien-Server, Kontrol Konkurensi, Serializability

Judul: Insecticidal Activity of Essential Oils Leaves of Cinnamomum spp. (Lauraceae) against Crocidolomia pavonana and Their Phytotoxicity on Broccoli Seedlings
Abstrak: Essential oils from leaves of 13 species of Cinnamomum were tested for their insecticidal activity on the cabbage head caterpillar Crocidolomia pavonana with leaf immerse method. The results showed that the treatment with 1% (w/v) essential oils leaves of C. celebicum, C. multiflorum, C. sintoc, and C. verum caused 21.45, 93.65, 60.30, and 76.10% mortality, respectively. Based on the results of phytotoxicity and insecticidal activity tests, C. multiflorum oil was further tested at 6 concentration levels. In all treatments, larval mortality has occurred at 24 hours after treatment (HAT) and increased at 48 HAT. LC50 of C. multiflorum oil at 24 and 48 HAT was 0.504 and 0.396%, respectively. The treatment with C. multiflorum oil at ≤0.31% did not inhibit the development of C. pavonana larvae. Determination of the chemical constituents of Cinnamomum oils were carried out by gas chromatography-mass spectrometry (GCMS). Totally, 345 compounds were identified. Methyleugenol constituted the main component (49.4%) of leaf essential oil of C. multiflorum and was assumed to be responsible for the insecticidal activity of the oil against C. pavonana larvae. LC50 of pure methyleugenol obtained at 0.365% (48 HAT) and 0.363% (72 HAT). The results showed that C. multiflorum was more effective with LC50 value equivalent to methyleugenol content of 0.32% (24 HAT) and 0.24% (48 HAT).
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