Machines and facilities are physically or chemically degenerated by continuous usage. One of the results of this degeneration is the process mean shift. By the result of degeneration, non-conforming products and malfunction of machine occur. Therefore a periodic preventive resetting the process is necessary. This type of preventive action is called ‘preventive maintenance policy.’ Preventive maintenance presupposes that the preventive (resetting the process) cost is smaller than the cost of failure caused by the malfunction of machine. The process mean shift problem is a field of preventive maintenance. This field deals the interrelationship between the quality cost and the process resetting cost before machine breaks down. Quality cost is the sum of the non-conforming item cost and quality loss cost. Quality loss cost is due to the deviation between the quality characteristics from the target value. Under the process mean shift, the quality cost is increasing continuously whereas the process resetting cost is constant value. The objective function is total costs per unit wear, the decision variables are the wear limit (resetting period) and the initial process mean. Comparing the previous studies, we set the process variance as an increasing concave function and set the quality loss function as Cpm+ simultaneously. In the Cpm+, loss function has different cost coefficients according to the direction of the quality characteristics from target value. A numerical example is presented.

곤충 머리에 있는 subgena (아랫뺨)와 clypeus (두순)는 연속된 피부판으로 통칭하여 peristome (입둘레판)으로 일컫는다. 따라서 subgenal sulcus (아랫뺨선)는 peristomal sulcus (입둘레홈) 또는 cranial-stomal sulcus (두개-입선)로 개정한다. 집파리류 성충 머리에 있는 ptilinal suture (이마주머니선)는 ptilinal fissure (얼굴주름)로 개정한다. 가슴에 있는 wing process (날개돌기)는 등판에 있는 것은 notal process (등판돌 기), 옆판에 있는 것은 pleural process (옆판돌기)로 각각 개정한다. 곤충 몸 아래쪽을 지칭하는 영역을 복부는 ventum (배판), 가슴은 sternum (가 슴판)으로 각각 지칭한다.

곤충의 머리를크게 cranium(머리겉뼈)과 mouth part(입틀)로 나눌 때 머리 겉뼈 부분을 frontoclypeal area(이마둔순부), parietals(머리옆뼈), occipital arch(뒷머리 아치), postocciput(뒷머리뒷판) 및 subgeneal area(아래뺨부)로 나누던 것 중 clpeus(얼굴앞판)와 subgeneal area(아래뺨부)를 입틀쪽으로 옮겨서 입틀을 peristome(입둘레)과 4개의 부속지(appendages)로 합치는 것이 타당할 것으로 생 각된다. 따라서 epistomal sulcus(입윗판홈)와 subgeneal sulcus(아래뺨홈)는 한 개의 연 결된 홈이므로 peristomal sulcus(입둘레홈) 또는 cranio-stomal sulcus(머리와 입 틀 사이홈)로 칭하는 것을 제안한다.