Tap chi KHKT Mo - Dia chdt, sd29, 01 /2010, tr. II I-/14
THONG TIN KHOA HOC Sir DUNG CAC DICH VU VA CAC GIAO THlTC TREN MANG TOAN CAU
Dfe TRUYEN TAI CAC BAN DO -WEBSITE
H A T H I MAI, PHAM T R A N H A I D U ' O N G
Trudng Dgi hoc Mo - Dia chdt
Tom tat: Cdc dich vu hien dang dugc sir dung di truyin tdi thdng tin trin mgng todn cdu that Id phong phii. Cdc nhd sdn xudt bdn do cdn phdi quan tdm tdi cdc dich vu ndy. Mgng that sir la mpt phirong tiin truyin tin rdt tiin tiin. Nd dd vd dang mang Igi nhiiu lai ich to Idn cho ngudi sir dung. Cdc bdn do cdn phdi dugc dua len mgng, di tgo thdnh cdc hi thong thdng tin todn cdu (Global Information System). Cdc bdn do a dgng website da ldm thay ddi cdch thirc sir dung vd cdng nghe sdn xudt bdn do. Cdc bdn do se dugc thiit ki theo nhiiu do hinh khdc nhau.
dugc thu'c hien het sii'c nhanh chong va de dang nha cac dich vu nhu web, mail, FTP, News, chat, conference,voice, over IP....
Mang Internet da thuc su mang lai Igi ich to Ion cho moi hoat dong san xuat, khoa hoc, giao duo, kinh doanh trong dai song xa hoi thong qua cac dich vu tren mang nhu:
Dich vu thu'dien tii- Electronic Mail (E-mail) E-mail la mot trong nhung tinh nang quan trong ciia mang Internet. Day la mot phuang phap truyen van ban tien loi nhat. Chi ton vai can, thu dien til' CO the giir den bat ky nai dau ttren trai dat [1]. Mot trong nhung Igi ich chinh ciia e-mail la toe do, tuy khong tu'c thdi nhu fax, nhung thai gian truyen cung chi vai phut. De thuc hien dieu nay nguai ta su' dung dich vu xac dinh ten va dia chi thu gii'i den thong qua viec danh ten viing nhu sau:
Ten_ngirdi_sir_dung@ Ten_ddy _du_ciiaJDomainWi du Nguyen van A thuoc Domain la hn.vnn.vn thi dja chi e-mail se la : [email protected]
Dich vu Mail List la mot trong nhu'ng dich vu ciia Internet co lien quan tdi cac nhom thao luan va toan bo du lieu dugc chuyen qua thu dien tir. Vai dia chi e-mail cua minh, ban co the dang ky tham gia mien phi vao cac nhom thao luan theo mot chii de nao do ma ban quan tam tai.
Dich vu Gorpher (Gorpher://...)
Gorpher la mot dich vu tra ciru thong tin tren mang theo chu de va sir dung cac menue [1]. Ngudi dung CO the sir dung Internet Gorpher Infermation Client v2.0.16 de tai cac thong tin ve may tinh ca nhan ciia minh. Mot han che ciia Gorpher la thong tin hien thi cho ngudi dung d dang cac menue nen cac thong tin rat han che va torn tat. Khi co djch vu Ban dd la mdt tai lieu kha dac biet va phirc
tap, nd chua dung nhieu loai dii' lieu khac nhau va dugc trdn lan vao nhau. Tdng lugng dir lieu cua ban do chiem mdt khdi lugng bd nhd khdng Id. Vi the, viec chuyen tai cac ban dd len mang toan cau theo cac dich vu mang can phai dugc nghien ciiu ky. Mat khac chinh ban do cung cd the la cdng cu mang cac thdng tin djch vu de phuc vu cac tra cuu tren dien rdng. Cac thdng tin tren ban do cd the phuc vu da nganh va da muc dich. Vi nhieu ly do tren, cac nha ban dd can phai tim hieu cac hinh thiic djch vu tren mang va nghien cuu each chuyen tai cac ban do len mang.
WWW Worid Wide Web la mang thong tin toan cau, hay con goi la Internet. Internet hoat dong dua tren sir ket noi cua hang chuc nghin may chii va he thong mang con d khap nai tren the gidi. Mang nay la nai cung cap cac thong tin rat da dang cho hang tram trieu ban doc d tit ca cac lu'a tuoi va trinh do khac nhau.
Mang Internet ngay nay la mot mang thdng tin toan cau. No dugc hinh thanh cuoi thap ky 60, tii' Bo Quoc phong My. Mang cho phep mot may tinh bat ky tren mang lien lac vdi moi may tinh khac. Mang internet hoat dong theo su quan ly chung ciia mot to chirc CO ten la InterNlC (International Network Information Commitee-Hiep hpi thong tin mang quoc te) [1]. Hiep hoi nay c6 quyen phan chia tai nguyen nhu: dia chi IP, so hieu mang, ten mien...) cho cac NIC khu vuc
Niu ai mu6n sir dung mang Internet thi phai dang ky thong qua cac NIC khu vuc va thong qua duv nhat mot giao thiic truyen thong chuan nhu TCP/IP. ^'0' su trao doi thong tin tren toan cau deu
www ra ddi thi dich vu Gorpher khong dugc sir dung rong rai niia.
Djch vu mang thong tin toan cau WWW World Wide Web day la mot dich vu mai nhat tren Internet. WWW dirge xay dung tren mot ky thuat c6 ten la Hypertext (sieu van ban). Hypertext la ky thuat trinh bay thong tin tren mot trang, trong do co mot so til' CO the nd ra thanh mot trang thong tin mdi cd noi dung day dii hon. Tren ciing mot trang co the CO nhieu loai kieu dir lieu. Cac du' lieu co the la tranh anh, nhac, chir, tieng ndi.... De xay dung dugc cac trang thong tin nhu tren, www su' dung mot ngon ngiJ dugc goi la HTML (Hypertext Markup Langguages). Ngon ngir HTML dugc xay dung tren ca sd ngon ngU SGML(Standard General Markup Langguage). HTML cho phep dinh dang va ket noi cac trang thong tin vdi nhieu loai du lieu khac nhau.
Tren cac trang thong tin co cac tii' cd the nd ra, dieu do CO nghTa la cac tir do co ket noi. De thuc hien viec ket noi nay www thuc hien mot ky thuat cd ten la URL (Universal Resource Locator) va giao thirc HTTP(Hyper text transfer Protocol).
HTTP (Hyper text transfer Protocol) la giao thuc truyen dan thong tin tren mang. Day la mot trong cac giao thiic dugc su' dung rong rai nhat hien nay. Cac may chu Web- Server se truyen tai cac ban do web len mang toan cau. Tiep theo, cac may khach hang se lay thong tin tir tren mang xuong, phan tich cac the theo ma HTML sau dd hien thi noi dung cac ban do ciing vdi cac hieu ung dong. Neu ban dgc co giri thong tin gi ve, thi may chii nhan lai vaphan tich tra ldi [3].
Ngudi sir dung cd the dung mot phan mem con dugc goi la cac Web Brower de hien thi cac thong tin da giri qua mang, tii cac may chii Web Servers.
Vdi sir bung no ciia dich vu www, dich vu nay cang dugc dua them vao nhieu ky thuat tien tien de tang kha nang bieu dat thdng tin cho ngudi sir dung.
Mot so cong nghe mdi dugc hinh thanh nhu Active X, Java, XML cho phep tao cac trang web dong, thuc su da md ra mot hudng rat Idn cho dich vu nay.
Dich vu truyen file -FTP (File Transfer Protocol) dugc diing de truyen tai cac files giua cac host tren Internet. Cong cu de thuc hien dich vu truyen file la chuang trinh FTP[1]. Chuang trinh nay sir dung giao thirc FTP (File Transfer Protocol).
Giao thirc nay cho phep truyen files khdng phu thiinr vao vi tri dja ly, moi trudng hay he dieu hanh.
L'..,i duy nhat la giira hai may co phan mem hieu dugc giao thirc FTP. Mot phan mem nhu vay cd tren he dieu hanh Unix va Windows.
De sir dung dich vu FTP ngudi sir dung o the dimg mot phin mem co ten lad FTP clieiii nhu:
WS_FTP va giao thiic FTP... .
Giao thirc FTP (File Transfer Protocol) la mot dich vu truyin tap tin tren he thdng mang Internet va tren cac he thdng mang TCP/IP. Ve ca ban, FTP la giao thuc client/server (khach/chii), trong do, mot he thdng dang sir dung tmh FTP server chap nhan cac yeu cau tir mot he thdng dang chay FTP client [2]. Dich vu nay cho phep nhieu ngudi diing giri din may chii cac yeu cau tai len (upload) hoac chep ve cac tap tin, hay con ggi la tai xudng (download). FTP hoat dgng giua nhieu loai he thong hdn hgp va cho phep ngudi diing tir he thong nay tuang tac vdi he thdng khac loai ma khong can quan tam den cac he dieu hanh tai do.
Dich vu Remove Login-Telnet cho phep ban ngoi tai may tinh ciia minh thuc hien ket ndi tdi mot may chii d xa (remote host) va thirc hien cac lenh tren may chii d xa nay, sau khi ban da login [1].
Nhiing gi ban go d may tinh cua ban se dugc chuyen tdi may chu d xa thuc hien va co tac dung nhu viec go tren chinh ban phim ciia ban. Ban co the truy nhap bat cu' dich vu gi ma may remove cho phep.
Djch vu nhom thong tin News (USENET) cho phep ngudi sii' dung ciing trao ddi cac thong tin ve mot chii de nao dd ma hg ciing quan tam. Ngudi diing chi can dang ky vao nhdm thdng tin va sau do ket ndi vao may chii de xem cac thong tin trong nhom va tai ve tram lam viec de xem chi tiet hoac gii'i cac thong tin cua minh len nhdm thong tin do.
Cac nhom thdng tin dugc xep theo thii' tu cha con.
Mdi nhom con dugc phan each vdi nhom cha bang mot dau cham (.).
Vl du nhu:
- Nhom Comp la nhdm cd chu'a cac thong tin ve computer, ve ky thuat phan mem va cac thong tin lien quan tdi mang.
- Nhdm New de cap tdi cac phan mem mdi, cac thong tin quan trgng cho ngudi diing.
- Nhdm Rec chii'a cac thong tin ve giai tri van hda nghe thuat... .
- Nhom SCI nhdm cac thdng tin ve nghien ciru khoa hgc.
- Nhom SOC la nhdm cac thong tin vi cac t6 chirc xa hdi, chinh trj ...
- Nhom m i s c la nhdm chira cac thdng tin khac ben trong.
Dich vu hoi thoai tren Internet la dich vu sir dung phuang tien Internet Relay Chat (IRC - noi chuyen qua Internet). Ban chi can ehd vai phiit sau 12
khi ^o lenh la ban co thi trao ddi thong tin vdi ngudi ban d rat xa va cdn co thi nhin thay hg. Cac thong tin trao ddi gan nhu la tire thdi. Dich vu nay con CO the tao cac kenh md cd nghTa la md hgi thoai cho 10 ngudi trd len.
Djch vu video confeerence la cau truyen hinh dugc thiet lap giira cac may tinh thong qua mang Internet vdi su trg giiip cua cac thiet bi ghi va hien hinh so. Khi dd, may tinh se ddng vai trd la cac may thu phat hinh anh da phuang tien, con moi trudng truyen thong tin dd la mang Internet thay vi sir dung cac may thu phat hinh truyen thdng.
Djch vu tim kiem thong tin tren dien rong (Wide Area Information Server-WAIS) cho phep ngudi sir dung tim kiem cac thong tin c6 trong cac CO sd du' lieu. Trong dich vu nay cac may chii WAIS se tu ddng xap sep cac tep tin dugc cap nhat vao trong cac ca sd du' lieu va tu ddng dm lai cac tep do tra thong tin ve cho ngudi sii' dung theo cac index ciia cac tep.
Djch vu E - Commerce (Electronic commerce - Thuong mai dien tii) dugc mo ta nhu sau:
Khach hang va the dien tii' -> mang Internet->
he thong ban hang va thu vien dien tLi'->he thong giao nhan tdi khach hang-> ban hang va thu tien.
Ban do vd'i mang toan cau
Nganh Ban dd cung nen dua cac ban do len mang den vdi cac ban dgc, thay ddi each thiic phan phoi va sii' dung ban dd. Su' dung cac dich vu rgng rai tren mang toan cau de truyen cac thdng tin ban do phuc vu ban dgc va phuc vu cac cugc hgp. Ban do cung CO the dugc gii'i nhu thu dien tii' den cac nai rat xa. Ngoai ra ban do cdn co the tao thanh he thong thdng tin khdng gian toan cau (Global Information System), hay cac thu vien dien tir toan cau....
Cac ban do dugc dua len mang cdn ggi la cac ban do-web. Mot he thong cac ban dd Idn du'gc ket noi vdi nhau theo md hinh mot site Idn cdn dugc ggi la ban do - website. Cac ban dd - website hoat dgng tuan theo md hinh chii- khach (Server-Client)
Ban do d dang website la mdt trong cac dang ban do da phuo'ng tien. Neu ban dd thiet ke tot cd the trd thanh cac ban dd tuang tac (interactive map).
Hoac ban dd tii'c thdi (real map, instance map)... . Cac ban dd d dang www co kha nang sir dung rgng rai va dac biet la khong doi hoi ngudi dgc phai CO trinh do cao ve ban do. Ban dd co the phuc vu dan dudiv quan ly giao thdng tren dja ban rgng Idn.
Ban dii ang www cdn la cong cu ndi va truyen
tin de quan ly tren dien rgng, phuc vu cac cong tac cixu hg, cuu nan, quan ly canh tac, tudi tieu. Ngoai ra no con la cong cu de phuc vu cho cdng tac da\- \-a hgc.
Cdc bdn do a dgng -www co hai dgng:
Dgng thu nhdt: Cdc bdn do co do Itinh client la cac ban do khdng dua len mang ma chi xuat ban d dang dTa CD (ban do cd do hinh client). Theo dd hinh client (hay cdn ggi la do hinh may khach hang) thi cac thdng tin ban dd khong bi tron qua may chii trudc khi hien thi ra man hinh. Cac ban do co hien thi dugc hay khong chi phu thudc cac chu'c nang xii' ly tren may tinh ciia khach hang, khdng phu thuoc vao may chii web. Loai dd hinh nay tuong ddi tien tien, thich ung vdi cac ban dd se xuat ban tren dTa CD.
Dgng thir hai: Cdc bdn do cd do hinh Ser\>er la cac ban dd dua Ien mang Internet hoac mang Intranet, hoac mang LAN (ban dd c6 do hinh server). Theo do hinh Server hay cdn ggi la do hinh may chu thi cac thdng tin trudc khi dugc hien thi tren may tinh ciia ngudi sii' dung deu phai bi tron qua may chii. Loai do hinh nay gay kho chju cho ngudi sir dung va chi thich u'ng vdi cac he thong ban do Idn de phuc vu muc dich quan ly tren dien rgng hoac quan ly cac ca sd dQ' lieu ban do.
Do hinh Server dugc sii' dung de trg giiip cho viec ket noi cac he thong thdng tin khong gian co tinh toan cau phuc vu cho muc dich tao ra trai dat so.
Ban dd tren mang vi co the truy cap nhanh nen dugc diing de quan ly giao thong, hudng dan dudng di, hudng dan cu'u hg, cii'u nan... . Cac thong tin mdi til' xa cdn cd the cap nhat va sira chua nhanh chong nen ban do mang trd thanh mot kenh thu thap cac thong tin mdi cd tinh tu'c thdi, phuc vu cho san xuat, dieu hanh cac hoat ddng thuang mai, dich vu va dac biet la phuc vu giao due.... Ban do tren mang toan cau thuc su mang lai nhieu Igi ich to Idn, nen cac nha ban do phai thuc su quan tam va chii y den ITnh vuc san xuat cac ban dd mang.
Cdc bdn do duoc dua len mgng trong hai dgng chinh la cac ban do d dang vector va cac ban dd d dang anh sd (rasters).
Cd ba hinh thdc dua bdn do len mgng:
Cac du' lieu ban dd trudc khi chuyen den cac may chu de cap len mang thudng phai trai qua mot qua trinh chuyen ddi tai cac cdng giao tiep chung hay cdn ggi la cac Gatervvay (xem hinh ve sd 1).
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Trang hdi dap cua may khach
HTTP HTML
weo server (May chii Web)
GIS
(Ca sd dir lieu ban do)
L ^ J Ket qua hdi dap Bien(Variables)
•
HTML
t
1
CGI 1
Gaterway
1
(Cdng giao tiip chung)
Hinh ve sd 1. Chuyin dii' lieu ban dd qua cdng giao tiep chung CGI- Common Gaterway Interface 2. Chuyin ban dd cimg vdi cac ung dung cd ten la cac Plug-in (xem hinh ve sd 2).
Web Brower (client) Search for Plug-In on
the Local sestem
HTTP Cac ddi tugng dugc gui Tai cac Plug-In
Data Display (Trinh dien ban do)
Web Server (May chii Web)
GIS Plug- In (Cac ling dung)
Hinh ve so 2. Hinh thiic chuyen cac ban do ciing vdi cac Plug-In
3. Cac ban dd dugc chuyin len mang trong cac trinh ung dung nhd dugc viet bSng Java Applet Web-browser (Client)
(May khach hang) < 1 HTML 1
HTTP * Web Server
(May chii)
Java Applet vaGIS Data displayed
Giii di cac iing dung (Java Applets) va GIS
Hinh ve sd 3. Hinh thuc chuyen cac ban dd qua cac iing dung ciia Java
[2]. Trudng dai hgc Bach khoa- Khoa Cdng nghe thdng tin. Le Tan Hiing, Dinh Thi Phuang Thu, Vii Dire Vugng, Huynh Quyet Thang. "Lap trinh ii'ng dung mang Internet khdng day". Nha xuat ban Khoa hgc-Ky thuat-2005.
[3]. Todd Stauffer. "Thiit ki va xuat ban Web 6 trong 1 vdi HTML". Nha xudt ban Thing Ke -2000.
Sau day la mot ban do thuc nghiem da dugc thiet ke va xay dung theo do hinh Server va sir dung giao thuc http. Ban do co ten ggi la "baigiang24B.htm". Ban do da dugc chuyen tai thanh cong theo giao thirc http.
TAI LIEU THAM KHAO
[I]. Cong ty dien toan va truyen sd lieu KVI. Tai lieu dao tao. "Tim hieu va khai thac hieu qua Internet". Ha Ngi-2000.
SUMMARY
Using Internet services and protocols for transfering maps - website Ha Thi Mai, Pham Tran Hai Duong, University of Mining and Geology
Internet is worid wide service. It has millions of users. It surport many services, which bring usefull and save time for everyone. Information from Internet comes to you in real time. So Cartographers have to consider and find solutions for bringing maps to users. Nowdays, Changing using methods of maps is necceessary and imfortant problem. This article will bring for you over view of all internet services and new interesting maps for readers.
Ngudi phan bien: Nguyen Trudng Xuan
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