THE PERFORMANCE OF SAWMILLS IS STRONGLY DEPENDENT ON HOW LOGS ARE SAWN INTO LUMBER IN ORDER TO SATISFY THE CUSTOMER DEMANDS. TO DO THIS, SAWMILL MANAGERS HAVE TO DECIDE WHICH CUTTING PATTERNS HAVE TO BE APPLIED TO LOGS OF DIFFERENT DIMENSIONS. OPTIMIZATION MODELS HAVE BEEN PROPOSED TO ASSIST DECISION MAKERS IN THIS PROCESS, BUT ONLY THE PROFIT MAXIMIZATION AND THE COST MINIMIZATION OF THE DECISIONS HAVE BEEN CONSIDERED AS THE MODELS OBJECTIVE. IN THIS PAPER, A LINEAR OPTIMIZATION MODEL WAS FORMULATED TO ADDRESS LUMBER PRODUCTION PLANNING AND APPLIED TO A REAL PROBLEM. THE CURRENT DECISIONS AT SAWMILLS WERE COMPARED WITH FIVE DIFFERENT OBJECTIVE FUNCTIONS: THE TWO PREVIOUSLY MENTIONED PLUS WASTE MINIMIZATION, LOG NUMBER MINIMIZATION AND PRODUCTION TIME MINIMIZATION. ONLY PROFIT MAXIMIZATION AND WASTE MINIMIZATION MODELS REPORTED POSITIVE ECONOMIC RETURNS. ALTHOUGH THE CURRENT DECISION AT SAWMILLS ALSO REPORTED A POSITIVE ECONOMIC RETURN, THE SAME ECONOMIC RESULT WAS OBTAINED WITH SIGNIFICANTLY FEWER RESOURCES USING THE WASTE MINIMIZATION MODEL. THE EFFECTS OF THE DIFFERENT OBJECTIVES ON THE PRODUCTION INDICATORS WERE DISCUSSED.

THE CUTTING PATTERN PROBLEM HAS BEEN TRADITIONALLY APPROACHED USING SINGLE OBJECTIVE OPTIMIZATION MODELS, ALTHOUGH THE SAWMILL PERFORMANCE IS USUALLY MEASURED USING MORE THAN A SINGLE INDICATOR. ONE OF THE SHORTCOMING OF USING MULTIOBJECTIVE APPROACHES IS THAT THEY NEED A PREFERENCE RELATIONSHIP AMONG THE OBJECTIVES, WHICH IS DIFFICULT TO DETERMINE IN PRACTICE, AND SOLUTIONS ARE VERY SENSITIVE TO THESE PREFERENCES. IN THIS ARTICLE, WE CONSIDER DIFFERENT CRITERIA IN A SAWMILL DECISIONMAKING CONTEXT USING A MULTIOBJECTIVE LINEAR OPTIMIZATION MODEL AND HANDLE THE UNCLEAR DEFINITION OF THE OBJECTIVE PREFERENCES BY FORMULATING A ROBUST VERSION OF THE MODEL. ALTHOUGH THE DETERMINISTIC FORMULATION ASSUMES PERFECT INFORMATION OF THE OBJECTIVE PREFERENCES, IN THE ROBUST FORMULATION WE CONSIDER THAT PREFERENCES MAY BE DIFFERENT FROM THEIR ESTIMATE. WE SHOW THAT DETERMINISTIC DECISIONS ARE MORE BALANCED IN TERMS OF THE DIFFERENT CRITERIA THAN THE TRADITIONAL SINGLE OBJECTIVE MODELS, ALTHOUGH THEIR QUALITY IS VERY SENSITIVE TO THE OBJECTIVE PREFERENCES. WE ALSO SHOW THAT ROBUST DECISIONS ARE ALSO BALANCED BUT LESS SENSITIVE TO THE PREFERENCES. WE EXPLORE HOW THE LEVEL OF THE DIFFERENT INDICATORS AND THE CUTTING DECISIONS ARE AFFECTED WHEN THE PREFERENCES ARE UNCLEAR.

ALTHOUGH OPTIMIZATION MODELS CAN BE USED TO PLAN THE PRODUCTION PROCESS, IN MOST CASES STATIC HEURISTICS, SUCH AS EARLIEST DUE DATE (E), LONGEST PROCESSING TIME (L), AND SHORTEST PROCESSING TIME (S), ARE USED BECAUSE OF THEIR SIMPLICITY. THIS STUDY AIMS TO ANALYZE THE PRODUCTION COST OF THE STATIC HEURISTICS AND TO DETERMINE HOW THIS COST RELATES TO THE SIZE OF THE PRODUCTION ORDERS IN THE SAWMILLING INDUSTRY. WE SET A PLANNING PROBLEM WITH DIFFERENT ORDERS AND DUE DATES AND SOLVED IT USING TWO COST-MINIMIZATION MODELS TO COMPARE THEIR SOLUTIONS. THE FIRST WAS A PLANNING MODEL (PL) WHERE ORDERS WERE SPLIT UP INTO PRODUCTS DEMAND BY PERIOD, AND THE SECOND, A PLANNING SCHEDULING (PS) WHERE THE SEQUENCE OF PROCESSING ORDERS BASED ON STATIC HEURISTICS WAS ASSUMED AS KNOWN. IN THE LATTER, THE MINIMUM PRODUCTION COST FOR EACH STATIC HEURISTIC WAS FOUND. IN BOTH MODELS, THE SAME RESOURCE CONSTRAINTS WERE ASSUMED. THE COSTS SHOWED NO SIGNIFICANT CHANGES BASED ON ORDER SIZES. HOWEVER, 0,5 % OF ORDERS WERE DELAYED USING PS-E, AND 17 % OF ORDERS WERE DELAYED USING PL. PL WAS AN EFFICIENT SOLUTION METHOD WHEN CHANGING THE ORDERS´ SIZE AND WHEN LOOKING FOR THE BEST STATIC HEURISTIC TO PROCESS THE ORDERS. HOWEVER, PS-E SHOWED THE ABILITY TO REDUCE THE BACKLOG CLOSE TO ZERO WHILE THE PL BACKLOG RATIO WAS 17 %. NO PENALTIES WERE APPLIED TO BACKLOGS DUE TO THEIR SUBJECTIVE NATURE; HOWEVER, WHEN SHORTAGES OCCURRED, THE DEMAND WAS UNMET OR BACKLOGGED WITH SUBSTANTIAL COSTS. THUS, IN CASE THE PROPOSED METHOD IS ADOPTED USING A CONSERVATIVE BACKLOG COST, A SAWMILL PRODUCING UNDER THE CUT-TO-ORDER ENVIRONMENT THAT PRODUCES 300000 M3 /YEAR WOULD REDUCE BACKLOGGED ORDERS BY 51000 M3. IF THE HOLDING LUMBER COST IS 2 $/M3, ANNUAL SAVINGS WOULD BE $408000.

IN THIS RESEARCH WORK AN ALGORITHM THAT GATHERS THE BEST PROCEDURES APPLIED IN SAWMILLS WAS DEVELOPED, ALONG WITH A METHODOLOGY BASED ON CUTTING GEOMETRICAL LINE ANALYSIS. THIS APPLICATION WAS PROGRAMMED UNDER THE C++ LANGUAGE, SIZES OBJECTIVE BOARD AND ITS PRICES, AND THE 2-D SLAB GEOMETRY ARE THE INPUT DATA, OBTAINING LENGTH AND WIDTH SOLUTIONS FOR EVERY SLAB. ITS OUTCOMES HAVE BEEN COMPARED WITH A PATTERN THAT MATCHES THE SOLUTIONS PROVIDED BY AN

THE SAWING OF HYMENAEA COURBARIL IS COMPLEX DUE TO ITS HIGH DENSITY AND ABRASIVENESS. THESE FACTORS ACCELERATE THE WEAR ON SAW BLADE TEETH, AND AS A CONSEQUENCE, INCREASE THE CUTTING VARIABILITY AND PROCESS COSTS. THE EFFECT OF CUTTING PARAMETERS ON STANDARD DEVIATION OF SAWN-WOOD THICKNESS WAS EVALUATED TO PROPOSE OPTIMAL SAWING CONDITIONS. A LOG CARRIAGE BANDSAW WITH TWO SAW BLADE GEOMETRIES, THREE LOG DIAMETER CLASSES, AND TWO FEED RATES WERE USED TO CARRY OUT THE SAWING TESTS. THE RESULTS SHOWED THAT THE SAWING VARIATION EXPRESSED BY THE TOTAL STANDARD DEVIATION OF BOARD THICKNESS WAS LOWER THAN 1 MM, WHEN LOG DIAMETER WAS LOWER THAN 0.79 M, AND THE LOG CARRIAGE FEED RATE WAS LOWER THAN OR EQUAL TO 10 M MIN-1 FOR BOTH SAW GEOMETRIES. THE SAWING THICKNESS WAS AFFECTED BY LOG DIAMETER AND LOG CARRIAGE FEED RATE, WHILE SAW GEOMETRY WAS NOT STATISTICALLY SIGNIFICANT. HOWEVER, THE GOAL OF THIS INITIATIVE WAS NOT AN ESTIMATION OF THE CHANGES ON SAWMILL PRODUCTIVITY. BEFORE THIS STUDY, ALL LOG CLASSES WERE PROCESSED WITH A LOG CARRIAGE FEED RATE OF NO HIGHER THAN 10 M MIN(-1). CONSEQUENTLY, GIVEN THE ESTIMATED TOTAL STANDARD DEVIATIONS, IT CAN BE SUGGESTED THAT THE LOGS OF CLASS 2 COULD BE SAWN AT A 50 % HIGHER RATE WITHOUT ALTERING THE CUTTING PRECISION, IMPROVING SAWMILL PRODUCTIVITY.

IN MANY INDUSTRIES, COMPANIES RECEIVE CUSTOMER ORDERS THAT INCLUDE MULTIPLE PRODUCTS. TO SIMPLIFY THE USE OF OPTIMIZATION MODELS FOR PLANNING PURPOSES, THESE ORDERS ARE BROKEN DOWN, AND THE QUANTITIES OF EACH PRODUCT ARE GROUPED WITH THE SAME PRODUCTS FROM OTHER ORDERS TO BE COMPLETED IN THE SAME PERIOD. CONSEQUENTLY, TRADITIONAL PRODUCTION PLANNING MODELS ENFORCE MINIMUM DEMAND CONSTRAINTS BY PRODUCT AND PERIOD RATHER THAN BY INDIVIDUAL ORDERS. AN IMPORTANT DRAWBACK OF THIS AGGREGATION PROCEDURE IS THAT IT REQUIRES A FIXED ORDER FULFILLMENT PERIOD, POTENTIALLY MISSING OPPORTUNITIES FOR MORE EFFICIENT RESOURCE USE THROUGH EARLY COMPLETION. THIS PAPER INTRODUCES A NOVEL MATHEMATICAL FORMULATION THAT PRESERVES THE INTEGRITY OF CUSTOMER ORDERS, ALLOWING FOR EARLY FULFILLMENT WHEN POSSIBLE. WE COMPARE A TRADITIONAL LINEAR PROGRAMMING MODEL WITH A NEW MIXED-INTEGER PROGRAMMING APPROACH USING A SAWMILL CASE STUDY. ALTHOUGH MORE COMPLEX THAN THE TRADITIONAL MODEL, THE PROPOSED FORMULATION REDUCES COSTS BY APPROXIMATELY 6% BY ENABLING EARLY ORDER COMPLETION AND OFFERS GREATER FLEXIBILITY AND CONTROL OVER THE PRODUCTION PROCESS. THIS APPROACH LEADS TO BETTER RESOURCE UTILIZATION AND MORE PRECISE ORDER MANAGEMENT, PRESENTING A VALUABLE ALTERNATIVE TO CONVENTIONAL PRODUCTION PLANNING MODELS.

IN THE FOREST SUPPLY CHAIN OF THE COAST OF BRITISH COLUMBIA, THE MATERIAL FLOWS ARE DIRECTED TOWARD THE PUSH PRODUCTION OF COMMODITY PRODUCTS. THIS INDUSTRY HAS NOT ADOPTED LEAN AND AGILE PRINCIPLES DUE TO UNCLEAR ECONOMIC IMPACTS ON THE SUPPLY CHAIN IN CHANGING MARKET CONDITIONS. WE TESTED THE ABILITY OF LEAN AND AGILE PRINCIPLES TO IMPROVE PERFORMANCE IN THE COASTAL INTEGRATED FOREST INDUSTRY. MIXED INTEGER PROGRAMMING FORMULATIONS WERE SUBJECT TO OVER?UNDER PRODUCTION CAPACITY, AND OVER?UNDER DEMAND FULFILLMENT PENALTIES TO EMULATE AGILE, LEAN, AND HYBRID MANUFACTURING ENVIRONMENTS, WHEN SOLVING THE PLANNING PROBLEM. ASSUMING THAT THE COASTAL INTEGRATED FOREST INDUSTRY PERFORMS AS A HYBRID ENVIRONMENT, THE PROFIT RESULTS OF EACH MANUFACTURING ENVIRONMENT WERE JUDGED. THE RESULTS SHOW THAT, OPPORTUNITIES FOR PROFIT IMPROVEMENT WERE 11% FOR ADOPTING AN AGILE ENVIRONMENT WHEN DEMAND WAS STABLE WITH LOW VARIATION AND LARGE BATCHES OF PRODUCTION. HOWEVER, PROFIT IMPROVEMENT WAS NON-EXISTENT WHEN THE SAME DEMAND ATTRIBUTES APPLY BUT WITH HIGH VARIATION. THE OPPORTUNITIES FOR PROFIT IMPROVEMENT WERE 12% WHEN AN AGILE ENVIRONMENT OR LEAN ENVIRONMENT WAS ADOPTED WHEN DEMAND WAS STABLE WITH LOW VARIATION AND SMALL BATCHES OF PRODUCTION. HOWEVER, OPPORTUNITIES FOR PROFIT IMPROVEMENTS OF 15% EXISTED FOR ADOPTING AN AGILE ENVIRONMENT WHEN DEMAND WAS UNSTABLE WITH HIGH VARIATION AND SMALL BATCHES OF PRODUCTION.

THE INSTITUTIONAL MANAGEMENT MODEL FOR RESEARCH AND INNOVATION IN HIGHER EDUCATION INSTITUTIONS IN LATIN AMERICA IS THE RESULT OF THE ERASMUS+ PROJECT, CO-FINANCED BY THE EUROPEAN UNION, IN WHICH 20 UNIVERSITIES, GOVERNMENT ENTITIES, AGENCIES AND ASSOCIATIONS FROM SPAIN, ITALY, SWEDEN, COLOMBIA, CHILE AND PERU PARTICIPATED, CALLED ?MODERNIZATION OF THE INSTITUTIONAL MANAGEMENT OF RESEARCH AND INNOVATION IN THE ANDEAN REGION OF LATIN AMERICA - MIMIR ANDINO?. IN THIS PUBLICATION, THE STAGES FOLLOWED IN THE CONSTRUCTION OF THE MODEL ARE BRIEFLY PRESENTED, AS WELL AS ITS GUIDING PRINCIPLES AND DIFFERENTIAL ELEMENTS. THE MODEL PROPOSES A MANAGEMENT THAT INTEGRATES FOUR COMPONENTS: STRATEGIC, EXECUTION, RELATIONAL AND ADMINISTRATIVE. REFLECTIONS AND SUGGESTIONS ARE INCLUDED IN EACH OF THE COMPONENTS TO BE CONSIDERED, ADAPTED OR APPLIED, WHEN DEEMED APPROPRIATE, WITHIN THE FRAMEWORK OF THE INSTITUTION?S AUTONOMY, TO IMPROVE ITS R&D&I MANAGEMENT. FINALLY, A SYNTHETIC MAP OF THE MODEL IS INCLUDED, AS WELL AS GENERAL RECOMMENDATIONS AND CLUES FOR ITS MONITORING AND IMPLEMENTATION. IT IS SUGGESTED TO USE THIS MODEL IN CONJUNCTION WITH THE INSTITUTIONAL SELF-ASSESSMENT INSTRUMENT FOR R&D&I MANAGEMENT MIMIR ANDINO, THAT CAN BE FOUND ON THE PAGES HTTPS://MIMIRANDINO.ORG AND HTTPS://ASCUN.ORG.CO.

SUSTAINABILITY HAS BECOME A KEY ISSUE IN THE FOREST INDUSTRY; THIS RESEARCH AIMS TO ANALYZE THE QUANTITATIVE TECHNIQUES AND METRICS APPLIED TO THE FOREST-TO-LUMBER SUPPLY CHAIN TO ACHIEVE SUSTAINABLE DECISION-MAKING DURING THE LAST SIX YEARS. THE METHODOLOGY USED WAS THE PRISMA SYSTEMATIC LITERATURE REVIEW GUIDE, WHICH PROVIDES A COMPLETE AND UPDATED VIEW OF THE SITUATION. A TOTAL OF 724 PUBLICATIONS WERE COLLECTED FROM THE WEB OF SCIENCE DATABASE. CONSEQUENTLY, 85 PAPERS WERE SELECTED FOR ANALYSIS AND SYNTHESIS AFTER APPLYING INCLUSION CRITERIA. THE RESULTS SHOW A GROWING INTEREST IN SUSTAINABILITY IN THE FOREST-TO-LUMBER SUPPLY CHAIN, WITH A PEAK OF PUBLICATIONS IN 2019. MATHEMATICAL PROGRAMMING AND SIMULATION MODELS ARE ON TOP OF THE QUANTITATIVE TECHNIQUES APPLIED. THESE TECHNIQUES ARE APPLIED TO THE SUPPLY CHAIN COMPONENTS, CLASSIFIED ACCORDING TO THE RAW MATERIAL?S DEGREE OF PROCESSING OR TRANSFORMATION LEVEL IN FOREST ENTITIES, SAWMILLS, TRANSPORTATION, AND OTHER ENTITIES. THE CONCLUDING REMARKS HIGHLIGHTED THAT 19 PUBLISHED WORKS RESEARCH THE SOCIAL DIMENSION, 43 EXPLORE THE ENVIRONMENTAL DIMENSION, AND 55 EXAMINE THE ECONOMIC DIMENSION. MOREOVER, IN THE ENVIRONMENTAL DIMENSION, THERE IS A CONCENTRATION ON THE USE OF METRICS ASSOCIATED WITH GREENHOUSE GASES, AND TO A LESSER EXTENT, THEY HAVE BEEN CONCERNED WITH SOIL AND WATER. ADDITIONALLY, IN THE SOCIAL DIMENSION, THEY HAVE CONCENTRATED MAINLY ON THE WORKERS, LEAVING THE LOCAL COMMUNITIES AROUND THE SUPPLY CHAIN IN THE SECOND PLACE. OUR SYSTEMATIC REVIEW REPORTS THE TECHNIQUES OR QUANTITATIVE METHODOLOGIES APPLIED IN THE FOREST-TO-LUMBER SUPPLY CHAIN AND THE METRICS USED TO HANDLE THE DIMENSIONS OF SUSTAINABILITY.

INTRODUCTION: WHEN SAWING LOGS WITHOUT DIAMETER SORTING, THE CUTTING PROGRAM GENERATES DECISIONS AND ROUTES DEPENDING ON THE LOG?S APPEARANCE AND MACHINE LOAD. OBJECTIVE: TO OPTIMIZE THE PRODUCTION FLOW OF A CUSTOM-CUT PINUS RADIATA D. DON SAWMILL, THROUGH DETECTION AND ANALYSIS OF CRITICAL MACHINES, USING DISCRETE EVENT SIMULATION AND EXPERIMENTAL DESIGN. MATERIALS AND METHODS: TWO SIMULATION MODELS WERE DEVELOPED FOR SAWING LOGS WITH LENGTHS OF 2.5 AND 5.0 M, AND DIAMETERS BETWEEN 34 AND 44 CM TO PRODUCE SAWNWOOD WITH A THICKNESS OF 5/4? WITH VARIABLE WIDTH. THE NUMBER OF LOGS PROCESSED PER SHIFT WAS THE RESPONSE VARIABLE OF THE MODEL. HEAVILY-USED MACHINES AND TRANSPORTS WITH LONG QUEUES WERE CANDIDATES FOR CRITICAL MACHINES. THE IMPACT ON PRODUCTION WAS DETERMINED BY MEANS OF EXPERIMENTAL DESIGN, WHERE THE FACTORS ASSESSED WERE: (A) DELIVERY FROM BANDSAW CARRIAGE 1 TO BAND SAW 3, (B) INCREASED DEBARKER CAPACITY, (C) FAILURES ELIMINATED FROM BANDSAW 1 AND 2, AND (D) DIRECT DELIVERY FROM BANDSAW 2 TO EDGER 2. RESULTS AND DISCUSSION: MODIFICATIONS TO THE PRODUCTION FLOW WERE PROPOSED BECAUSE FACTORS B, C AND D SIGNIFICANTLY INCREASED (P = 0.1) THE PRODUCTION LEVEL (LOGS PER SHIFT); THE INCREASES OVER THE SAWMILL?S INITIAL CONDITION WERE 13 AND 18 % FOR LENGTHS OF 2.5 AND 5.0 M, RESPECTIVELY. CONCLUSION: SIMULATION AND EXPERIMENTAL DESIGN CAN BE APPLIED IN SMALL AND MEDIUM-SIZED SAWMILLS TO IMPROVE PRODUCTION WHEN PROCESSING LOGS WITHOUT DIAMETER SORTING.