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Herjanto, Eddy. (2006) Manajemen Operasi Edisi Ketiga. Jakarta : PT. Gramedia Widiasarana Indonesia Rangkuti, Freddy. (2007) Manajemen Persediaan. Jakarta: PT RAJAGRAFINDO PERSADA Kusuma, Hendra. (2009) Manajemen Produksi Perencanaan & Pengendalian Produksi. Yogyakarta : ANDI Gaspers, Vincent. (2012) Production Planning and Inventory Control. Jakarta : Gramedia Pustaka Utama. Heizer, Jay. & Render, Barry Render. (2005) Manajemen Operasi Edisi Ketujuh Buku 2. Jakarta : Salemba Empat Haming, Murdifin. & Mahfud Nurnajamuddin. (2007) Manajemen Produksi Modern (Operasi Manufaktur dan Jasa). Jakarta : Bumi Aksara Sugiyono (2009) Metode Penelitian administrasi. Bandung : CV Alfabeta Jurnal dan Skripsi :
Sagbansua, Lutfu & M. Nurettin Alalabay. (2010). An MRP Model for Supply
Chains. (School of Economics and Administrative Sciences, Turki)
Oladokun, V.O & O.A Olaitan. (2012). Development of a Materials Requirements
Planning (MRP) Software. (University of Ibadan, Nigeria)
E.D, Dinesh & Arun A.P, Pranav R. (2014). Material Requirement Planning for
Automobile Service Plant. (Kumaraguru College of Technology, India)
Limbong, Inggried & H. Tarore, J. Tjakra, D. R. O. Walangitan. (2013). Manajemen Pengadaan Material Bangunan Dengan Menggunakan Metode MRP (Material Requirement Planning) Studi Kasus: Revitalisasi Gedung Kantor BPS Propinsi Sulawesi Utara. (Universitas Sam Ratulangi, Manado)
Surianto, Agus. (2013). Penerapan Metode Material Requirement Planning (MRP) di PT. Bokormas Mojokerto. (Universitas Brawijaya, Malang) Ruhul Ummiroh, Isnaini. (2013). Analisis Penerapan Material Requirement
Planning (MRP) Pada Pennyellow Furniture. (Universitas Jember, Jember)
Dian Wijaya, Dilzar. (2006). Analisis Pengendalian Persediaan Bahan Baku Susu Kental Manis Pada PT. Indomilk. (Institut Pertanian Bogor, Bogor) Taryana, Nanang. (2008). Analisis Pengendalian persediaan Bahan Baku Pada Produk Sepatu Dengan Pendekatan Teknik Lot Sizing Dalam Mendukung Sistem MRP(Studi Kasus di PT. Sepatu Mas Idaman, Bogor). (Institut Pertanian Bogor, Bogor) Amalia, Alona. (2013). Analisa Pengendalian Persediaan Bahan Baku MCSET AD1 12.5 kV dengan Menggunakan Metode Forecast dan Material Requirement
Planning di PT. Schneider Indonesia. (Universitas Mercu Buana, Jakarta)
Irawan, Andy. (2014). Usulan Perencanaan Persediaan Bahan Baku Tinta Sakata dengan Menggunakan Metode Material Requirement Planning (MRP).
(Universitas Mercu Buana, Jakarta) Agung S, Akbar. (2009). Penerapan Metode Single Moving Average dan Exponential Smothing Dalam Peramalan Permintaan Produk Meubel Jenis Coffe Table pada Java Furniture Klaten . (Universitas Sebelas Maret, Surakarta) Website:
http://bisnis.liputan6.com/read/2191512/2-perusahaan-telekomunikasi-merugi-gara-gara-penguatan-dolar-as ( diakses pada 10 Desember 2015) https://indosatooredoo.com/id/about-indosat/company-profile/history ( diakses pada 28 November 2015) http://taufiqurrachman.weblog.esaunggul.ac.id/wp-content/uploads/sites/968/2013/10/EMA302-4-Peramalan-Forecasting-2-Exe.pdf ( diakses
64 LAMPIRAN Lampiran 1 : Perhitungan Peramalan
Bulan Produksi Aktual (A) Januari 15,491,435 Febuari 8,115,495 Maret 14,100,053 April 14,240,846 Mei 9,249,529 Juni 25,558,159 Juli 5,933,333 Agustus 9,691,006 September 10,293,913 Oktober 13,286,418 November 11,162,021 Desember 17,532,579 Total 154,654,788
A. Perhitungan Peramalan Model Pemulusan Exponensial (Exponential Smoothing) dengan α = 0.1 F Januari ’15 = 15,491,435+ 0.1 (8,115,495 - 15,491,435) = 14,753,841 F Febuari ’15 = 14,753,841 + 0.1 (15,491,435 - 14,753,841 ) = 14,827,600.5 = 14,827,601 F Maret ’15 = 14,827,601+ 0.1 (8,115,495 - 14,827,601) = 14,156,390.4 = 14,156,390 dan seterusnya.
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B. Perhitungan Peramalan Model Pemulusan Exponensial (Exponential Smoothing) dengan α = 0.5 F Januari ’15 = 15,491,435+ 0.5 (8,115,495 - 15,491,435) = 11,803,465 F Febuari ’15 = 11,803,465 + 0.5 (15,491,435 - 11,803,465 ) = 13,647,450 F Maret ’15 = 13,647,450 + 0.5 (8,115,495 - 13,647,450 ) = 10,881,472.5 = 10,881,473 dan seterusnya.
C. Perhitungan Peramalan Model Pemulusan Exponensial (Exponential Smoothing) dengan α = 0.9 F Januari ’15 = 15,491,435+ 0.9 (8,115,495 - 15,491,435) = 8,853,089 F Febuari ’15 = 8,853,089 + 0.9 (15,491,435 - 8,853,089 ) = 14,827,600.5 = 14,827,601 F Maret ’15 = 14,827,601 + 0.9 (8,115,495 - 14,827,601 ) = 8,786,705.6 = 8,786,706 dan seterusnya.
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D. Perhitungan Peramalan Produksi Tahun 2016
F Januari ’16 = 15,491,435+ 0.1 (8,115,495 - 15,491,435) = 14,753,841 F Febuari ’16 = 14,753,841 + 0.1 (15,491,435 - 14,753,841 ) = 14,827,600.5 = 14,827,601 F Maret ’16 = 14,827,601+ 0.1 (8,115,495 - 14,827,601) = 14,156,390.4 = 14,156,390 dan seterusnya.
E. Perhitungan Peramalan Produksi Tahun 2017
F Januari ’17 = 14,753,841+ 0.1 (14,827,601 - 14,753,841) = 14,761,217 F Febuari ’17 = 14,761,217 + 0.1 (14,753,841 - 14,761,217 ) = 14,760,479.5 = 14,760,480 F Maret ’17 = 14,760,480+ 0.1 (14,827,601 - 14,760,480) = 14,767,192.1 = 14,767,192 dan seterusnya.
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Lampiran 2 : Perhitungan MAD
Periode (2015) Produksi Aktual (A) Peramalan Dibulatkan dengan α = 0.1 Peramalan Dibulatkan dengan α = 0.5 Peramalan Dibulatkan dengan α = 0.9 At-Ft (α = 0.1) At-Ft (α = 0.5) At-Ft (α = 0.9) |At-Ft| (α = 0.1) |At-Ft| (α = 0.5) |At-Ft| (α = 0.9) Januari 15,491,435 14,753,841 11,803,465 8,853,089 737,594 3,687,970 6,638,346 737,594 3,687,970 6,638,346 Febuari 8,115,495 14,827,601 13,647,450 14,827,601 -6,712,105 -5,531,955 -6,712,105 6,712,105 5,531,955 6,712,105 Maret 14,100,053 14,156,390 10,881,473 8,786,706 -56,337 3,218,580 5,313,347 56,337 3,218,580 5,313,347 April 14,240,846 14,150,756 12,490,763 13,568,718 90,090 1,750,084 672,128 90,090 1,750,084 672,128 Mei 9,249,529 14,159,765 13,365,805 14,173,634 -4,910,236 -4,116,275 -4,924,104 4,910,236 4,116,275 4,924,104 Juni 25,558,159 13,668,742 11,307,667 9,741,940 11,889,417 14,250,492 15,816,219 11,889,417 14,250,492 15,816,219 Juli 5,933,333 14,857,684 18,432,913 23,976,537 -8,924,351 -12,499,580 -18,043,204 8,924,351 12,499,580 18,043,204 Agustus 9,691,006 13,965,248 12,183,123 7,737,653 -4,274,243 -2,492,117 1,953,352 4,274,243 2,492,117 1,953,352 September 10,293,913 13,537,824 10,937,064 9,495,670 -3,243,911 -643,151 798,243 3,243,911 643,151 798,243 Oktober 13,286,418 13,213,433 10,615,489 10,214,089 72,985 2,670,929 3,072,329 72,985 2,670,929 3,072,329 November 11,162,021 13,220,732 11,950,953 12,979,185 -2,058,710 -788,932 -1,817,164 2,058,710 788,932 1,817,164 Desember 17,532,579 13,014,861 11,556,487 11,343,738 4,517,718 5,976,091 6,188,841 4,517,718 5,976,091 6,188,841 154,654,788 47,487,698 57,626,158 71,949,384 3,957,308 4,802,180 5,995,782 ∑ Absolute Devition MAD (n = 12)
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Lampiran 3 : Perhitungan MSE
Periode (2015) Produksi Aktual (A) Peramalan Dibulatkan dengan α = 0.1 Peramalan Dibulatkan dengan α = 0.5 Peramalan Dibulatkan dengan α = 0.9 At-Ft (α = 0.1) At-Ft (α = 0.5) At-Ft (α = 0.9)
(At-Ft ^2) (α = 0.1) At-Ft ^2 (α = 0.5) At-Ft ^2 (α = 0.9)
Januari 15,491,435 14,753,841 11,803,465 8,853,089 737,594 3,687,970 6,638,346 544,044,908,836 13,601,122,720,900 44,067,637,615,716 Febuari 8,115,495 14,827,601 13,647,450 14,827,601 -6,712,105 -5,531,955 -6,712,105 45,052,358,900,709 30,602,526,122,025 45,052,358,900,709 Maret 14,100,053 14,156,390 10,881,473 8,786,706 -56,337 3,218,580 5,313,347 3,173,875,597 10,359,258,503,832 28,231,658,042,680 April 14,240,846 14,150,756 12,490,763 13,568,718 90,090 1,750,084 672,128 8,116,200,172 3,062,792,256,972 451,756,204,318 Mei 9,249,529 14,159,765 13,365,805 14,173,634 -4,910,236 -4,116,275 -4,924,104 24,110,418,946,634 16,943,722,757,018 24,246,803,043,039 Juni 25,558,159 13,668,742 11,307,667 9,741,940 11,889,417 14,250,492 15,816,219 141,358,240,745,967 203,076,522,954,589 250,152,792,033,413 Juli 5,933,333 14,857,684 18,432,913 23,976,537 -8,924,351 -12,499,580 -18,043,204 79,644,034,400,571 156,239,502,363,827 325,557,216,824,379 Agustus 9,691,006 13,965,248 12,183,123 7,737,653 -4,274,243 -2,492,117 1,953,352 18,269,153,041,551 6,210,649,353,443 3,815,584,749,704 September 10,293,913 13,537,824 10,937,064 9,495,670 -3,243,911 -643,151 798,243 10,522,957,803,167 413,643,108,309 637,191,916,219 Oktober 13,286,418 13,213,433 10,615,489 10,214,089 72,985 2,670,929 3,072,329 5,326,825,873 7,133,864,068,451 9,439,206,724,400 November 11,162,021 13,220,732 11,950,953 12,979,185 -2,058,710 -788,932 -1,817,164 4,238,288,525,570 622,414,143,166 3,302,085,292,978 Desember 17,532,579 13,014,861 11,556,487 11,343,738 4,517,718 5,976,091 6,188,841 20,409,778,067,387 35,713,669,135,484 38,301,755,300,022 154,654,788 344,165,892,242,033 483,979,687,488,014 773,256,046,647,576 28,680,491,020,169 40,331,640,624,001 64,438,003,887,298 ∑ Square Error MSE ( n = 12 )
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Lampiran 4 : Perhitungan MAPE
Periode (2015) Produksi Aktual (A) Peramalan Dibulatka n dengan α = 0.1 Peramalan Dibulatka n dengan α = 0.5 Peramalan Dibulatka n dengan α = 0.9 At-Ft (α = 0.1) At-Ft (α = 0.5) At-Ft (α = 0.9) |At-Ft| (α = 0.1) |At-Ft| (α = 0.5) |At-Ft| (α = 0.9) Absolute Percentage Error (α = 0.1) Absolute Percenta ge Error (α = 0.5) Absolute Percenta ge Error (α = 0.9) Januari 15,491,435 14,753,841 11,803,465 8,853,089 737,594 3,687,970 6,638,346 737,594 3,687,970 6,638,346 4.761 23.807 42.852 Febuari 8,115,495 14,827,601 13,647,450 14,827,601 -6,712,105 -5,531,955 -6,712,105 6,712,105 5,531,955 6,712,105 82.707 68.165 82.707 Maret 14,100,053 14,156,390 10,881,473 8,786,706 -56,337 3,218,580 5,313,347 56,337 3,218,580 5,313,347 0.400 22.827 37.683 April 14,240,846 14,150,756 12,490,763 13,568,718 90,090 1,750,084 672,128 90,090 1,750,084 672,128 0.633 12.289 4.720 Mei 9,249,529 14,159,765 13,365,805 14,173,634 -4,910,236 -4,116,275 -4,924,104 4,910,236 4,116,275 4,924,104 53.086 44.503 53.236 Juni 25,558,159 13,668,742 11,307,667 9,741,940 11,889,417 14,250,492 15,816,219 11,889,417 14,250,492 15,816,219 46.519 55.757 61.883 Juli 5,933,333 14,857,684 18,432,913 23,976,537 -8,924,351 -12,499,580 -18,043,204 8,924,351 12,499,580 18,043,204 150.410 210.667 304.099 Agustus 9,691,006 13,965,248 12,183,123 7,737,653 -4,274,243 -2,492,117 1,953,352 4,274,243 2,492,117 1,953,352 44.105 25.716 20.156 September 10,293,913 13,537,824 10,937,064 9,495,670 -3,243,911 -643,151 798,243 3,243,911 643,151 798,243 31.513 6.248 7.755 Oktober 13,286,418 13,213,433 10,615,489 10,214,089 72,985 2,670,929 3,072,329 72,985 2,670,929 3,072,329 0.549 20.103 23.124 November 11,162,021 13,220,732 11,950,953 12,979,185 -2,058,710 -788,932 -1,817,164 2,058,710 788,932 1,817,164 18.444 7.068 16.280 Desember 17,532,579 13,014,861 11,556,487 11,343,738 4,517,718 5,976,091 6,188,841 4,517,718 5,976,091 6,188,841 25.768 34.086 35.299 154,654,788 458.895 531.235 689.794 38.241 44.270 57.483 ∑ Absolute Percentage Error
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Lampiran 5 : Perhitungan Tracking Signal
Periode Produksi Aktual (A) Peramalan Dibulatkan dengan α = 0.1 At-Ft (α = 0.1) RSFE |At-Ft| (α
= 0.1) MAD (t) MAD Tracking Signal Tracking Signal (t) Januari 15,491,435 14,753,841 737,594 737,594 737,594 61,466 61,466 12.000 0.186 Febuari 8,115,495 14,827,601 -6,712,105 -5,974,511 6,712,105 559,342 620,808 -9.624 -1.696 Maret 14,100,053 14,156,390 -56,337 -6,030,849 56,337 4,695 625,503 -9.642 -0.014 April 14,240,846 14,150,756 90,090 -5,940,759 90,090 7,507 633,011 -9.385 0.023 Mei 9,249,529 14,159,765 -4,910,236 -10,850,995 4,910,236 409,186 1,042,197 -10.412 -1.241 Juni 25,558,159 13,668,742 11,889,417 1,038,422 11,889,417 990,785 2,032,982 0.511 3.004 Juli 5,933,333 14,857,684 -8,924,351 -7,885,928 8,924,350 743,696 2,776,677 -2.840 -2.255 Agustus 9,691,006 13,965,248 -4,274,243 -12,160,171 4,274,242 356,187 3,132,864 -3.881 -1.080 September 10,293,913 13,537,824 -3,243,911 -15,404,082 3,243,911 270,326 3,403,190 -4.526 -0.820 Oktober 13,286,418 13,213,433 72,985 -15,331,097 72,985 6,082 3,409,272 -4.497 0.018 November 11,162,021 13,220,732 -2,058,710 -17,389,807 2,058,710 171,559 3,580,832 -4.856 -0.520 Desember 17,532,579 13,014,861 4,517,718 -12,872,089 4,517,719 376,477 3,957,308 -3.253 1.142 154,654,788 167,526,877 -3.253
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Lampiran 6 : Perhitungan EOQ Diketahui :
Kebutuhan tahun 2017 (D) = 174,615,035
Biaya pemesanan/setup (S) = Rp. 30,000,- perpesanan Biaya penyimpanan (H) = Rp. 26,- pertahun perunit EOQ : 𝑄 = √ 2𝐷𝑆 − 𝐻 𝑄 = √ 2 x 174,615,035 x 30,000 − 26 𝑄 = √ 2 x 174,615,035 x 30,000 − 26 𝑄 = 634,789.55 𝑄 = 634,790 Frekuensi Pemesanan : 𝐹 = 𝐷 𝑄 𝐹 = 174,615,035 634,790 𝐹 = 275.075 𝐹 = 276
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Detail Pemesanan :
Bulan Kebutuhan kotor
Proyeksi persediaan ditangan Kebutuhan Bersih frekuensi pemesanan Total pemesanan tiap bulan Desember 24 15,234,960 Januari 14,761,217 15,234,960 0 23 14,600,170 Febuari 14,760,480 473,743 14,286,737 23 14,600,170 Maret 14,767,192 313,433 14,453,759 23 14,600,170 April 14,706,112 146,411 14,559,701 24 15,234,960 Mei 14,650,576 40,469 14,610,107 23 14,600,170 Juni 14,601,495 624,853 13,976,642 22 13,965,380 Juli 14,508,220 623,528 13,884,692 23 14,600,170 Agustus 14,543,166 80,688 14,462,478 23 14,600,170 September 14,485,374 137,692 14,347,682 23 14,600,170 Oktober 14,390,619 252,488 14,138,131 22 13,965,380 November 14,272,901 462,039 13,810,862 23 14,600,170 Desember 14,167,684 154,518 14,013,166 276
