Judul: The Expected Value of the Queueing Length on the M/M/1 Queue Model Which Can be Repaired by Considering the Damage Level
Abstrak: Suatu antrean terjadi karena jumlah pelanggan yang datang melebihi jumlah fasilitas yang disediakan. Sistem dapat diandalkan saat server mungkin mengalami kegagalan atau kerusakan dan server dapat segera diperbaiki. Pada karya ilmiah ini, ditinjau sistem antrean M/M/1 yang dapat diperbaiki dengan mempertimbangkan tingkat kerusakan, dengan proses kedatangan pelanggan berdistribusi Poisson. Saat server mengalami kerusakan pada waktu kosong atau waktu sibuk, server segera menuju proses perbaikan. Setelah periode perbaikan selesai, server kembali dengan kondisi baru dan dapat melanjutkan sistem. Kemudian, dengan menyelesaikan persamaan diferensial untuk fungsi pembangkit peluang pada peluang steady-state, formulasi dari nilai harapan panjang antrean pada sistem dapat diperoleh. Simulasi numerik pengaruh parameter terhadap nilai harapan panjang antrean menunjukkan bahwa perubahan panjang antrean dan laju waktu perbaikan sensitif terhadap laju pelayanan, serta panjang antrean rata-rata dipengaruhi oleh laju tingkat kerusakan pada waktu sibuk dan laju waktu perbaikan., A queue occurs because the number of customers who come exceeds the number of provided facilities. The system can be relied on when the server may experience failure or damage, but it can be repaired immediately. In this manuscript, the M/M/1 queuing system that can be repaired by considering the level of damage is reviewed, where the customers arrival process is Poisson distributed. When the server crashes at an idle time or busy time, the server immediately goes to the repairing process. After the repairing process is over, the server returns with a new condition and the server’s operation can be continued. Furthermore, by solving the differential equation for the probability generating function at steady-state probability, the formulation of the expected value of the queue length in the system can be obtained. Numerical simulation of the effect of parameters on the expected value of queue length shows that changes in queue length and repairing time are sensitive to service rates, and the average queue lengths usually are affected by damage rates at busy times and repairing times rate.
Keyword: queue, probability generating function, expected value, repairable system

Judul: Analysis of M/M/1 Queue System with Continuous Service
Abstrak: Sistem antrean M/M/1 dengan pelayanan kontinu adalah sistem antrean di mana waktu pengiriman dan layanan secara independen dan menyebar secara eksponensial dengan satu server, sehingga server melayani pelanggan saat pelanggan berada di dalam sistem. Untuk mencapai karakteristik tersebut, diasumsikan di dalam sistem tersebut ada dua jenis pelanggan, yaitu pelanggan nyata dan pelanggan imajiner. dst..., The M/M/1 queueing system with continuous service is a queuing system where delivery and service times are independent and exponentially distributed with one server, so that the server serves the customer while the customer is in the system. To achieve the mentioned characteristics, it is assumed in the system there are two types of customers, namely real customers and imaginary customers. dst...
Keyword: expected value, exponentially, probability density function, queue

Judul: Waxes, policosanols and aldehydes in sugarcane (Saccharum officinarum L.) and okinawan brown sugar (kokuto)
Abstrak: Waxes, long chain alcohols and aldehydes were found in several variants of sugarcane (Saccharum officinarum L.) and Kokuto, a non-centrifuged Okinawan cane brown sugar. Long chain alcohols, policosanols, have been reported to have beneficial effect to human health. The composition of wax in sugarcane was analyzed using HPLC with an evaporative light scattering detector. Sugarcane wax composed of 55–60% aldehydes, sterol esters and wax esters, 32–40% alcohols, and small amounts of triacylglycerols, acids and sterols. Extraction of policosanols performed effectively with hexane and methanol (20:1 v/v), while that of long chain aldehydes was with chloroform and methanol (2:1 v/v). Their composition was determined using GC with a flame ionization detector, whereas their compounds were identified using GC-MS. Sugarcane rinds contained up to 500 mg policosanols and 600 mg aldehydes per 100 g sample of Ni 22 cultivar. The content of policosanol and long chain aldehyde in Kokuto was influenced by its production systems. Compositional analysis of the end product confirmed the presence of policosanols and aldehydes up to 85 mg and 8 mg respectively per 100 g sample of Kokuto A, a product of brown sugar manufacture with open pan heating system. Octacosanol and octacosanal were found to be the major wax components in both sugarcane and Kokuto samples. This study revealed significant difference in content and composition of waxes, policosanols and long chain aldehydes between sugarcane parts, cultivars and harvesting times; also between Kokuto types and production methods.
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