• 제목/요약/키워드: supply delay

검색결과 298건 처리시간 0.029초

첨단교통체계(ITS)에 의한 도시고속도록의 Ramp Metering 시스템 구축에 관한 연구 (The Ramp Metering System Construction of Urban Freeway by the Intelligent Transportation System (ITS) Technology)

  • 김태곤
    • 한국항만학회지
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    • 제13권2호
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    • pp.333-350
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    • 1999
  • Today freeway is thought to be a very important transportation facility carrying tremendous traffic flow as the main corridor within the area of between the areas. However freeway is experiencing severe congestion and accidents by increased entrance ramp flow especially at peak time period. Ramp meters on the freeway entrance ramps that supply traffic to the freeway in a measured or appropriately regulated amount are needed for alleviating freeway congestion. Because ramp meters can be operated to discharge traffic at a measured or regulated rate thus maintaining more uniform speed on the mainline section maximizing the throughput to the freeway within the capacity of a downstream bottleneck and reducing the congestion related accidents. Thus the objectives in this study were to analyze the traffic characteristics on the freeway I-94 with ramp metering system before/after ITS technology in Detroit (Michigan) area compare shifts of the traffic characteristics on the freeway I-94 before/after ITS technology and finally suggest a better ramp metering strategy for the freeway system The following results were obtained: i)Flow occupancies and speeds on the mainline merge section of freeway were shown to be a big difference depending on the peak periods areas and directions based on the distribution of traffic flow characteristics on the freeway. ii)Reduced speed was shown to be more than 5 mph and ramp flow was also shown to be more than 240 vph at peak periods if there was the ramp metering system constructed on the freeway. iii)Ramp metering system was shown to be optimally operated on the freeway if ramp flow could be maximized within the range of over 900 vph and reduced occupancy could be also maximized by no more than 2 percent at peak periods. iv)The average flows on the freeway after the ITS technology were shown to be a decrease of over 20% depending on the peak periods areas and directions when compared with those flow on the freeway before the ITS technology. over 20% depending on the peak periods areas and directions when compared with those speeds on the freeway before the ITS technology. vi)The average metering rates on the freeway after the ITS technology were shown to be an increase of over 10% depending on the peak periods areas and directions when compared with those metering rates on the freeway before the ITS technology.

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10-비트 200MS/s CMOS 병렬 파이프라인 아날로그/디지털 변환기의 설계 (The Design of 10-bit 200MS/s CMOS Parallel Pipeline A/D Converter)

  • 정강민
    • 정보처리학회논문지A
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    • 제11A권2호
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    • pp.195-202
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    • 2004
  • 본 연구에서 매우 정밀한 샘플링을 필요로 하는 고해상도 비디오 응용면을 위하여 병렬 파이프라인 아날로그 디지털 변환기(ADC)를 설계하였다. 본 ADC의 구조는 4 채널의 10-비트 파이프라인 ADC를 병력 time-interleave로 구성한 구조로서 이 구조에서 채널 당 샘플링 속도의 4배인 200MS/s의 샘플링 속도를 얻을 수 있었다. 변환기에서 핵심이 되는 구성요소는 Sample and Hold 증폭기(SHA), 비교기와 연산증폭기이며 먼저 SHA를 전단에 설치하여 시스템 타이밍 요구를 완화시키고 고속변환과 고속 입력신호의 처리론 가능하게 하였다. ADC 내부 단들의 1-비트 DAC, 비교기 및 2-이득 증폭기는 한 개의 switched 캐패시터 회로로 통합하여 고속동작은 물론 저 전력소비가 가능한 특성을 갖도록 하였다. 본 연구의 연산증폭기는 2단 차동구조에 부저항소자를 사용하여 높은 DC 이득을 갖도록 보강하였다. 본 설계에서 각 단에 D-플립플롭(D-FF)을 사용한 지연회로를 구성하여 변환시 각 비트신호를 정렬시켜 타이밍 오차를 최소화하였다. 된 변환기는 3.3V 공급전압에서 280㎽의 전력소비를 갖고 DNL과 INL은 각각 +0.7/-0.6LSB, +0.9/-0.3LSB이다.

Strain-Relaxed SiGe Layer on Si Formed by PIII&D Technology

  • Han, Seung Hee;Kim, Kyunghun;Kim, Sung Min;Jang, Jinhyeok
    • 한국진공학회:학술대회논문집
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    • 한국진공학회 2013년도 제45회 하계 정기학술대회 초록집
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    • pp.155.2-155.2
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    • 2013
  • Strain-relaxed SiGe layer on Si substrate has numerous potential applications for electronic and opto- electronic devices. SiGe layer must have a high degree of strain relaxation and a low dislocation density. Conventionally, strain-relaxed SiGe on Si has been manufactured using compositionally graded buffers, in which very thick SiGe buffers of several micrometers are grown on a Si substrate with Ge composition increasing from the Si substrate to the surface. In this study, a new plasma process, i.e., the combination of PIII&D and HiPIMS, was adopted to implant Ge ions into Si wafer for direct formation of SiGe layer on Si substrate. Due to the high peak power density applied the Ge sputtering target during HiPIMS operation, a large fraction of sputtered Ge atoms is ionized. If the negative high voltage pulse applied to the sample stage in PIII&D system is synchronized with the pulsed Ge plasma, the ion implantation of Ge ions can be successfully accomplished. The PIII&D system for Ge ion implantation on Si (100) substrate was equipped with 3'-magnetron sputtering guns with Ge and Si target, which were operated with a HiPIMS pulsed-DC power supply. The sample stage with Si substrate was pulse-biased using a separate hard-tube pulser. During the implantation operation, HiPIMS pulse and substrate's negative bias pulse were synchronized at the same frequency of 50 Hz. The pulse voltage applied to the Ge sputtering target was -1200 V and the pulse width was 80 usec. While operating the Ge sputtering gun in HiPIMS mode, a pulse bias of -50 kV was applied to the Si substrate. The pulse width was 50 usec with a 30 usec delay time with respect to the HiPIMS pulse. Ge ion implantation process was performed for 30 min. to achieve approximately 20 % of Ge concentration in Si substrate. Right after Ge ion implantation, ~50 nm thick Si capping layer was deposited to prevent oxidation during subsequent RTA process at $1000^{\circ}C$ in N2 environment. The Ge-implanted Si samples were analyzed using Auger electron spectroscopy, High-resolution X-ray diffractometer, Raman spectroscopy, and Transmission electron microscopy to investigate the depth distribution, the degree of strain relaxation, and the crystalline structure, respectively. The analysis results showed that a strain-relaxed SiGe layer of ~100 nm thickness could be effectively formed on Si substrate by direct Ge ion implantation using the newly-developed PIII&D process for non-gaseous elements.

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어선 기관실의 연기 거동에 관한 수치해석 연구 (A Numerical Study on Smoke Behavior of Fishing Vessel Engine Room)

  • 장호성;지상원
    • 해양환경안전학회지
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    • 제27권5호
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    • pp.683-690
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    • 2021
  • 선박 기관실 통풍 설계조건 및 계산 기준에 관한 국제 표준(ISO 8861)을 만족해야 하는 선박 기관구역의 환기시스템은 일반적으로 내연기관에 필요한 연소공기의 공급과 기관구역에서 발생한 열원을 제거하기 위해 설치되며 화재감지기가 포함된 환기시스템의 응답지연은 구역 내부에 형성된 기류와 화재감지기의 설치 위치에 영향을 받는다. 어선에서 발생하는 화재는 상선과 비교하여 인명피해 가능성이 높으므로 화재 조기 감지가 무엇보다 중요하다. 따라서 본 논문에서는 어선에 설치되는 화재 감지기의 초기 화재감지 응답속도 향상과 설치된 감지기의 감도 유지를 위해 기관구역 내부에서 발생한 정량적 연기량에 따른 공기 유동장, 내연기관 연소 공기량 및 기관 구역 내부 압력을 변수로 연기 거동 시뮬레이션이 가능한 해석모델을 구성하여 선박 기관구역 내부의 연기 거동을 시뮬레이션하였다. 시뮬레이션 결과를 통해 기관실 내부 압력을 감소시키고 연기커튼 설치를 통해 공기 유동장에서의 유속을 감소시키고 와류를 증가시키면 연기 성분의 천장 상승이 가속화되어 연기감지기 응답속도 및 환기시스템이 개선될 수 있을 것으로 해석되었다.

태양광전원 수용을 위한 MVDC 배전망의 경제성평가 모델링에 관한 연구 (A Study on Economic Evaluation Modeling of MVDC Distribution System for Hosting Capacity of PV System)

  • 이후동;김기영;김미성;노대석
    • 한국산학기술학회논문지
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    • 제22권3호
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    • pp.1-12
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    • 2021
  • MVDC 배전기술은 현재 급격하게 도입되고 있는 태양광전원의 접속지연 문제를 해결하기 위한 효과적인 대안으로 평가되고 있지만, DC 배전망용 기기들을 개발해야 하므로 DC 배전망의 구축비용은 경제적인 측면에서의 문제점을 가지고 있다. 따라서, 본 논문에서는 태양광전원의 수용을 위한 MVDC 배전망의 도입 타당성을 평가하기 위하여, 태양광전원 단지를 용량에 따라 규모별로 정의하고, 이를 수용하기 위한 배전망을 건설하는 경우에 대하여 규모별로 수용성 모델을 제시한다. 이 모델은 배전망의 전원공급방식에 따라 AC 및 DC 배전망으로 구분되며, 수용할 태양광전원 단지의 용량에 따라 수백 MW급은 대규모, 수십 MW급은 중규모, 수 MW급은 소규모로 정의된다. 또한, 본 논문에서는 AC 및 DC 배전망의 건설비, 전력변환설비의 교체비, 운용비로 구성된 비용요소와 태양광전원의 발전수익에 따른 전력량 요금 및 REC 요금으로 구성된 편익요소를 고려하여 MVDC 배전망의 경제성평가 모델링을 제시한다. 이를 바탕으로 현재가치 환산법과 원금균등상환 방식을 이용하여 MVDC 배전망의 경제성을 평가한 결과, 태양광전원의 수용 규모에 따라 일정 연계거리 이후에서는 DC 배전망의 구축비용이 기존의 AC 배전망보다 경제적임을 알 수 있어, 본 논문에서 제시한 경제성평가 모델링의 유용성을 확인하였다.

통영 세병관 초석의 암석학적 특성 및 비파괴 손상평가 (Petrological Characteristics and Nondestructive Deterioration Assessments for Foundation Stones of the Sebyeonggwan Hall in Tongyeong, Korea)

  • 한두루;김성한;박석태;이찬희
    • 자원환경지질
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    • 제54권2호
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    • pp.199-212
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    • 2021
  • 세병관(국보 제305호)은 통영 삼도수군통제영에 위치하며, 1605년에 창건한 이래 최근까지 수차례의 중건, 중수, 보수 및 복원을 거쳤다. 연구대상인 세병관 초석은 모두 50개로 다양한 표면손상이 나타난다. 이 초석은 총 6개의 암종으로 구성되어 있으며, 대부분은 석영안산암질 래피리 응회암이다. 보수용 대체석 수급을 위한 산지해석 결과, 대부분의 암석은 초석과 산출상태, 기재적, 광물학적 및 전암대자율 등 암석학적으로 높은 동질성을 갖는 것으로 나타났다. 초석의 손상유형 중에는 표면의 박리와 박락이 가장 심한 것으로 나타났으며, 무기오염물 분석을 통한 손상메커니즘으로 볼 때 해풍 및 복합적인 환경에 의한 염풍화가 주된 원인으로 판단된다. 초석의 기계적 내구성으로 보아 현재 물성 저하로 부재의 교체가 필요한 것은 없으나 표면적인 손상을 늦추기 위한 보존처리가 필요할 것으로 보인다. 이 초석은 표면에 발생한 물리적 손상과 내부 결함을 유발하는 암석학적 요인이 복합적으로 작용하였다. 따라서 세병관의 장기적 보존을 위해서는 주기적인 상태 진단과 모니터링이 요구된다.

항만분야 공공갈등 관리방안 도출에 관한 연구 (A Study on Derivation of Public Conflict Management Countermeasure in the Port Sector)

  • 김가현;김세원;이혜령
    • 한국항해항만학회지
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    • 제47권4호
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    • pp.246-255
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    • 2023
  • 항만분야에서 발생하는 공공갈등은 추가적인 사회적 비용 유발과 함께 항만 인프라 적기 공급을 지연시켜 지역산업 및 국가 경쟁력에 부정적 영향을 미칠 수 있다. 점차 항만분야의 갈등관리 중요성이 커지고 있음에도 불구하고 아직까지 체계적인 갈등관리방안은 부재한 상황이다. 이에 본 연구에서는 현재 항만분야 갈등관리체계의 한계점을 고찰하고 항만분야 정책 담당자, 갈등관리 전문가지방청 및 항만공사의 개발·계획 담당자, 해양수산부 갈등관리 종합시책 관련 담당자, 갈등관리 전문가 및 업계전문가를 대상으로 델파이 조사를 수행하여 항만분야에서 발생하는 갈등을 진단할 수 있는 기준, 갈등발생원인, 사전적 관리방안과 사후적 해소방안을 도출했다. 델파이 조사 결과, 갈등 발생의 가장 큰 원인은 '이해관계자 의견수렴 및 협의, 소통 수단 부재'로 나타났다. 사전적 갈등관리방안은 '구체적 사안 결정 전, 지역 의견 수렴과 발전방향을 논의하기 위한 공론화 절차 진행'이, 사후적 갈등해소방안으로는 '갈등원인 조사, 대안 마련 과정에 현지 주민 및 객관적 인사 등을 포함시켜 신뢰성을 확보하는 것'이 가장 중요한 것으로 도출되었다. 나아가 본 연구에서는 도출된 결과를 바탕으로 항만개발사업 단계별 갈등관리기법을 제시했으며 이는 현재까지 국무조정실의 「공공기관 갈등관리 매뉴얼(2016)」에는 포함되어 있지 않은 항만분야를 반영하는데 유용한 참고자료로 활용될 수 있을 것으로 생각된다.

대동맥수술에서의 수술 중 신경계감시의 적용 (Application of Intraoperative Neurophysiological Monitoring in Aortic Surgery)

  • 장민환;채지원;임성혁
    • 대한임상검사과학회지
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    • 제54권1호
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    • pp.61-67
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    • 2022
  • INM은 수술의 안정성을 더해주고 고위험군의 수술을 안전하게 진행할 수 있게 도움을 주고 있다. INM검사가 적용이 되는 모든 수술에서의 수술 과정과 신경학적 결손이 발생할 수 있는 과정에서 집중적으로 검사를 진행해 보다 신속하게 수술자에게 알리지 않으면 손상이 되었을 때 그에 대한 대처가 늦어서 환자에게 돌이킬 수 없는 심각한 후유증을 가져다 줄 수 있다. 대동맥류 및 대동맥 박리로 발생되는 대동맥 치환술은 개흉 및 개복술이 진행되며 심장의 혈류를 차단하는 매우 위험한 수술이다. 대동맥에서 분지되어 척수에 혈류를 공급하는 혈관들을 교체할 때 척수로 가는 혈류가 감소해 척수 허혈이 올 수 있다. 대동맥 수술에서의 INM은 겸자시에 유발전위를 이용하여 빠르게 척수 허혈이 시작되는 시점을 찾아내고 수술자에게 보고해 척수 허혈을 방지하며 심각한 합병증을 막는 중요한 역할을 수행한다. 이에 수술의 과정과 TceMEP, SSEPs의 검사 방법 및 검사 시점, 검사 기준에 대하여 작성을 하여 INM을 시행하는 검사자들에게 도움이 되고자 본문을 작성하였다. 본문으로 인해 대동맥수술에서 INM의 필요성, 대동맥 수술에서의 흐름을 파악하고 정확하고 신속한 검사를 통한 보고로 원활한 검사가 진행되길 바라는 바이다.

신생아의 조기수유에 관한 실험적 연구 (An Experimental Study on the Early Feeding of Infants)

  • 하영수
    • 대한간호학회지
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    • 제5권1호
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    • pp.1-16
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    • 1975
  • The newborn human is the only mammalian whose mother does not have a food supply ready for it's offspring at birth. From two to four days usually elapse before the mother's supply If milk appears, and during this period, some kind of artificial feeding should be supplied to the infants. Because of this factor, there has been continued debate fog the past hundreds of years as to when the first feeding should be started Accordingly, many experiments were carried out by scholars and because of these, Pre-lateral feedings were believed to be necessary. Many types of pre-lateral feedings were tried and the conclusion was reached that glucose water was the best food for the first infants'feedings. Traditionally, This has been started 12 hours after birth. The causes for the 12 hours delay were thought to (1) provide rest for the infants: (2) prevent regurgitation ana vomiting which tended to be prevalent during this tine: (3) in cases of low weight infants, prevention of aspiration pneumonia. From recent studies of newborn physiology and as pediatric medicine has been rapidly advancing, many studies hare been carried out concerning the improvement of infant nutrition and the early feeding of infants has been emphasized. This author believes it would be very beneficial to try two different kinds of feedings for the infant. (1) experimental feedings ana (2) comparative feeding, and during this period to investigate and compare the infants blood sugar level, hematocrit, gamma globulin level weight changes and to observe the infant reaction ill order to search for a more desirable feeding program. This study was conducted from January to March 1974 with data related to 40 healthy newborn infants (male 21, female 19: weight, 2.79∼4.20㎏ : gestation, 39∼40 weeks) born at Ewha Womens University Hospital and the results obtained were as follows : 1. At time of birth the blood sugar level from the cord sample averaged 88.99㎎/100㎖, but the blood sugar level rapidly dropped after 2 to 3 hours and reached the lowest point after 10 to 11 hours (54.48㎎/100㎖) and rose again by the 24 hour time period (76.80㎎/100㎖). Changes in the blood sugar level of the experiments: groups and the compare-five group was not significantly different until the 6 to 7 hour period, but by the 10 to 11 hour period the blood sugar levels of the experimental group (49,10㎎/100㎖) and the comparative group (49.70㎎/100㎖) were lower than the remainder of the experimental groups. 9. There ware no significant weight changes between the two groups. Average weight at birth was 3.35㎏, but at the 24 hours period birth weight averaged 3.29㎏. (1.8% reduction of birth weight). It continually lowered until at 48 hours, average weight was 3.26㎏ (2.7% reduction from birth weight.) 3. Hematocrit readings showed no significant difference between the groups. Hematocrit, the average value at birth, was 28.07% and abruptly elevated to average 64.35% at the 2 to 3 hour period, then slowly lowered to an average of 59.67% at the 6 to 7 hour period, 55.10% at the 10 to 11 hour period, ana 53.70% at the 24 hour period. 4. At birth, average gamma globulin value averaged 1,39㎎/100㎖. and at the 24 hour period averaged 1,52㎎/100㎖ revealing no significant difference between the two feeding groups. 5. Such factors as voiding, passing of meconium, regurgitation and vomiting showed no significance between the two feeding groups. However, the number of infants voiding and passing meconium in the experimental groups during the first 12 hours was slightly greater. In general there was an increased tendency for regurgitation and. vomiting among a small group of the infants during the first 24 hours which thereafter decreased. 6. Fluid intake averaged 24.38cc at the first feeding and increased to average 30.48cc at the third feeding and further increased to 73. 00cc at the fifteenth feeding. Finally it was suggested that the most reasonable method of early feeding is to give less than 25cc of 5% glucose water and/or 8% powdered milk at 8 to 9 flours after birth in order to prevent hypoglycemia and dehydration.

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식재료 아웃소싱이 경제적 주방에 미치는 영향에 관한 연구 - 특1급호텔 양식조리를 중심으로 - (Study on economic effects of outsourcing of food materials on the hotel kitchen - Focus on cooking Western food in the first class hotel -)

  • 성태종
    • 한국관광식음료학회지:관광식음료경영연구
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    • 제13권2호
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    • pp.45-69
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    • 2002
  • This study is designed to examine feasibility and limitation of outsourcing in cooking Western food in a hotel, to interpret importance of outsourcing(eg. outside order, outside procurement, outside supply) in a broad sense in order to reinforce the core capacity in the cooking department, and to know whether the cooking human power is efficiently used and how much the chefs recognize outsourcing of food materials. As many companies conduct restructuring to cut down its size, the reduction of human power led the Western food cooking in the hotel to lower core capacities, lower quality, and lower efficiency. In addition, the sagging morale of chefs undermined creativity. To change from the traditional kitchen to an economic kitchen needs to look into importance of outsourcing, cognitive attitude of chefs, relation with outside suppliers. Here suggests performance of positive changes in the structure The study examined feasibility and limitation of outsourcing in the hotel kitchen as well as chefs' cognitive attitude toward outsourcing of food materials to reinforce core capabilities of the hotel kitchen. 1. Companies of outsourcing are selected according to variability of price conditions, flexibility of contract conditions, popularity of the outsourcing company, and reputation of the outsourcing company. 2. The importance of outsourcing in the Western food cooking is divided into 4 factors such as standard of selecting outsourcing companies, policies of cooking manu, quality of cooking, and quantity of cooking. 3. The most feasible section in outsourcing of food materials is a process of kneading flour for bread, which shows that many Western-food chefs expect to put higher possibility of outsourcing on the kneading. In other words, when it comes to confectionery and bakery, there are many outside expert processing companies supplying high quality products. In the order of outsourcing feasibility, sauce is followed by processed vegetable, garnish of main dish, and soup. The least feasible section in outsourcing of food materials is appetize. Appetize includes a concept of a improvised dish and needs speed. Due to its color, freshness, and sensibility of taste, the appetize plays a key role in the Western food cooking. 4. When outsourcing is taken in place, the highest risk is to lower the inner cooking skills. Therefore chefs in charge of the Western food sequently recognize both internal problems including storage of cooking skills, unstability of layoffs, and loss of cooperation between departments, and external problems including inferior goods, difficulty of differentiating manu, delay of delivery, and expiration date. It shows that most of the Western food chefs consider risks of the internal problems at first. 5. A effective outsourcing needs appropriate selection of outsourcing companies, maintenance of credibility, active communication, check and management of hygiene. However regardless of their position or career, chefs in charge of the Western food have the same cognitive attitude toward selecting successful outsourcing companies after the outsourcing system is enforced. The core of cooking, or a final stage in the full process of so-called artistic cooking, should be treated with insourcing. Reduction of several cooking processes resulted in shortened cooking time, increased efficiency, faster cooking, cutting the waiting-lines, and finally more room for customers. The outsourcing system can reduce or eliminate the following processes in cooking: buying various food materials, checking, storing, preparing, and processing. Especially in the Western food cooking department of a hotel, the outsourcing system should be enforced to make an economic kitchen and to efficiently manage it. Wow it's time to change from the traditional kitchen to an economic kitchen in the hotel cooking department. For that, the cooking department should become a small but strong organization by outsourcing except its core work.

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